GUIDELINES ON SANITATION
AND HEALTH
GUIDELINES ON SANITATION AND HEALTH
Safe sanitation is essential for health, from preventing infection to improving and maintaining mental and
social well-being.
Developed in accordance with the processes set out in the WHO Handbook for Guideline Development,
these guidelines provide comprehensive advice on maximizing the health impact of sanitation interventions.
They summarize the evidence on the links between sanitation and health, provide evidence-informed
recommendations, and offer guidance for international, national and local sanitation policies and
programme actions. The guidelines also articulate and support the role of health authorities in sanitation
policy and programming to help ensure that health risks are identied and managed eectively.
The audience for the guidelines is national and local authorities responsible for the safety of sanitation
systems and services, including policy makers, planners, implementers within and outside the health sector
and those responsible for the development, implementation and monitoring of sanitation standards and
regulations.
Department of Public Health, Environmental and Social Determinants of Health
World Health Organization
Avenue Appia 20
1211 Geneva 27
Switzerland
http://www.who.int/phe
ISBN 978 92 4 151470 5
WHO
GUIDELINES ON SANITATION
AND HEALTH
Guidelines on sanitation and health
ISBN 978-92-4-151470-5
© World Health Organization 2018
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III
CONTENTS
Contents
Foreword........................................................................... vii
Acknowledgements .................................................................... viii
Acronyms and abbreviations ................................................................ x
Executive summary .................................................................... xii
Chapter 1. Introduction ................................................................... 1
1.1 The signicance of sanitation for human health ............................................ 1
1.2 Sanitation as a human development issue ............................................... 2
1.3 Scope .................................................................... 4
1.4 Objectives ................................................................. 6
1.5 Target audiences ............................................................. 7
1.6 Health authorities mandate ....................................................... 7
1.7 Methods .................................................................. 7
1.8 Guidelines structure ............................................................ 8
References .................................................................... 9
Chapter 2. Recommendations and good practice actions ............................................. 11
2.1 Recommendations ........................................................... 11
2.2 Good practice actions .......................................................... 20
References ................................................................... 26
Chapter 3. Safe sanitation systems ........................................................... 29
3.1 Introduction ............................................................... 29
3.2 Toilets .................................................................. 31
3.3 Containment – storage/treatment ................................................... 34
3.4 Conveyance ............................................................... 39
3.5 Treatment ................................................................ 44
3.6 End use/disposal ............................................................ 49
3.7 Applicability of sanitation systems ................................................... 52
References ................................................................... 57
Chapter 4. Enabling safe sanitation service delivery ................................................ 59
4.1 Introduction ............................................................... 59
4.2 Components of an implementation framework ............................................ 59
4.3 Policy and planning ........................................................... 61
4.4 Legislation, regulations, standards and guidelines .......................................... 64
4.5 Roles and responsibilities ........................................................ 68
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WHO GUIDELINES ON SANITATION AND HEALTH
4.6 Environmental health authorities and their role in sanitation .................................... 70
4.7 Delivering sanitation at local level ................................................... 74
4.8 Developing sanitation services and business models ......................................... 75
4.9 Fostering the sanitation services market ................................................ 78
4.10 Management of special sanitation risks ................................................ 79
References ................................................................... 83
Chapter 5. Sanitation behaviour change ....................................................... 84
5.1 Introduction ............................................................... 84
5.2 Institutional and government responsibilities for sanitation behaviour change .......................... 84
5.3 Sanitation behaviours and determinants ............................................... 85
5.4 Changing behaviours .......................................................... 87
5.5 Monitoring and learning for success .................................................. 95
References ................................................................... 97
Chapter 6. Excreta-related pathogens ......................................................... 100
6.1 Introduction ............................................................... 100
6.2 Microbial aspects linked to sanitation ................................................. 102
6.3 Environmental transmission of pathogens in faecal waste ...................................... 114
6.4 Treatment and control ......................................................... 120
References ................................................................... 122
Chapter 7. Methods .................................................................... 125
7.1 Introduction ............................................................... 125
7.2 Contributors ............................................................... 125
7.3 Scoping and question formulation ................................................... 126
7.4 Evidence retrieval, assessment and synthesis ............................................. 128
7.5 Evidence grading ............................................................ 128
7.6 Evidence-to-Decision (EtD) framework ................................................ 130
References ................................................................... 132
Chapter 8. Evidence on the eectiveness and implementation of sanitation interventions ........................ 133
8.1 Introduction ............................................................... 133
8.2 Summary and discussion of evidence ................................................. 133
8.3 Reviews of intervention eectiveness ................................................. 134
8.4 Reviews of implementation ...................................................... 141
8.5 Summary of evidence reviews ..................................................... 142
References ................................................................... 150
Chapter 9. Research needs ................................................................ 151
9.1 Pursuing a sanitation research agenda................................................. 151
9.2 Research agenda ............................................................ 151
References ................................................................... 157
V
CONTENTS
Annexes
Annex 1: Sanitation system fact sheets ................................................... 159
Annex 2: Glossary ............................................................... 193
Tables
Table 1.1: The health impact of unsafe sanitation ............................................... 2
Table 2.1: Evidence to recommendation table using the WHO-INTEGRATE framework .......................... 23
Table 3.1: Treatment performance of containment technologies ..................................... 37
Table 3.2: Established wastewater treatment technologies ........................................ 46
Table 3.3: Established sludge treatment processes ............................................. 47
Table 3.4: Summary of established end use products ............................................ 50
Table 3.5: Applicability of sanitation systems ................................................ 53
Table 3.6: Examples of climate adaptation options for specic sanitation systems ............................ 54
Table 4.1: Areas that may require legislation and regulation ........................................ 64
Table 5.1: Summary of approaches and factors for consideration in their implementation ....................... 90
Table 5.2: Behavioural monitoring methods and measures ........................................ 96
Table 6.1: Excreta-related pathogens .................................................... 105
Table 6.2: Pathogen concentrations in faeces and raw sewage ....................................... 116
Table 6.3: Factors inuencing microbial persistence ............................................ 118
Table 6.4: Selection of ID50 values from human challenge data ...................................... 119
Table 7.1: Evidence to recommendation table using the WHO-INTEGRATE framework .......................... 131
Table 8.1: Summary of evidence reviews .................................................. 143
Figures
Figure 1.1: Transmission of excreta-related pathogens ............................................ 4
Figure 1.2: Sanitation service chain ...................................................... 5
Figure 3.1: Faecal contamination risk .................................................... 30
Figure 3.2: Excreta ow diagram showing examples of hazardous events at each step of the sanitation service chain ......... 30
Figure 3.3: Hazardous events for permeable and impermeable containment - storage/treatment technologies ............ 35
Figure 3.4: Hazardous events for conveyance technologies ......................................... 41
Figure 4.1: Categorization of sanitation services ............................................... 60
Figure 4.2: Implementation framework for sanitation ........................................... 61
Figure 4.3: Example of phasing out unsafe sanitation over time ...................................... 63
Figure 4.4: Sanitation service chain regulatory mechanism options .................................... 66
Figure 4.5: The components of the SDG sanitation ladder ......................................... 73
Figure 5.1: Example of behavioural determinants for open defecation .................................. 87
Figure 5.2: Stages in behaviour change strategy design .......................................... 92
Figure 6.1: Transmission of excreta-related pathogens ........................................... 103
Figure 7.1: Conceptual framework for guidelines development ...................................... 127
Figure 8.1: Preliminary conceptual framework of the inuence of inadequate sanitation on well-being ................ 141
Figure 8.2: Sanitation adoption and sustained use review framework ................................... 142
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WHO GUIDELINES ON SANITATION AND HEALTH
Boxes
Box 1.1: Sanitation and complex health outcomes: environmental enteric dysfunction .......................... 1
Box 1.2: Human right to sanitation ...................................................... 3
Box 1.3: The Sustainable Development Goals (SDGs) and sanitation ..................................... 3
Box 1.4: Why are guidelines on sanitation and health needed? ....................................... 6
Box 3.1: International Organization for Standardization (ISO) standards relevant for sanitation services ................ 29
Box 3.2: Denitions .............................................................. 30
Box 3.3: Climate change, sanitation and health ............................................... 54
Box 4.1: Setting targets ............................................................ 62
Box 4.2: Immediate preventive measures for areas at high risk of enteric disease outbreaks ....................... 81
Box 5.1: Sanitation behaviour change considerations for urban settings ................................. 87
Box 6.1: Antimicrobial resistance and sanitation .............................................. 101
VII
FOREWORD
Foreword
S
anitation saves lives. But history teaches us that it’s also one of the key
building blocks of development.
Ancient civilizations that invested in sanitary improvements became healthy,
wealthy, powerful societies. More recently, modernization and economic growth
have followed investments in sanitation systems.
Sanitation prevents disease and promotes human dignity and well-being, making it
the perfect expression of WHO’s denition of health, as expressed in its constitution,
as “A state of complete physical, mental, and social well-being, and not merely the
absence of disease or inrmity”.
The right to water and sanitation is foundational to several Sustainable
Development Goals. After decades of neglect, the importance of access to safe
sanitation for everyone, everywhere, is now rightly recognized as an essential
component of universal health coverage. But a toilet on its own is not sucient
to achieve the SDGs; safe, sustainable and well-managed systems are required.
Globally, billions of people live without access to even the most basic sanitation services. Billions more are
exposed to harmful pathogens through the inadequate management of sanitation systems, causing people to
be exposed to excreta in their communities, in their drinking water, fresh produce and through their recreational
water activities. The scale of need is further compounded by urbanization, climate change, antimicrobial
resistance, inequality and conict.
It is with these challenges in mind WHO has developed its rst comprehensive guidelines on sanitation and
health, lling a critical gap in authoritative health-based guidance on sanitation that results in better health.
While clearly setting out the need for action and providing tools and resources, these guidelines also reinvigorate
the role of health authorities as champions of sanitation.
The guidelines recognize that safe sanitation systems underpin the mission of WHO, its strategic priorities
and the core mission of ministries of health globally. I hope these guidelines will be of great practical use to
ministries, health authorities and implementers to make the best investments in the best interventions for the
best possible health outcomes for everyone.
Dr Tedros Adhanom Ghebreyesus
Director-General
World Health Organization
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WHO GUIDELINES ON SANITATION AND HEALTH
Acknowledgements
Guidelines Development Group
Patrick Apoya, Consultant, Ghana; Jamie Bartram, The Water Institute at the University of North Carolina, USA;
Jay Bhagwan, Water Research Commission, South Africa; Lizette Burgers, UNICEF, USA; Alfred Byigero, Rwanda
Utilities Regulatory Authority, Rwanda; Kelly Callahan, The Carter Center, USA; Renato Castiglia Feitosa,
Fiocruz, Brazil; Thomas Clasen, Rollins School of Public Health, Emory University, USA; Oliver Cumming, London
School of Hygiene & Tropical Medicine, UK; Robert Dreibelbis, Department of Disease Control, London School
of Hygiene and Tropical Medicine; Peter Hawkins, independent consultant, UK; Tarique Huda, International
Centre for Diarrhoeal Disease Research, Bangladesh; Andrés Hueso, WaterAid, UK; Paul Hunter, the University
of East Anglia, UK; Pete Kolsky, The Water Institute at the University of North Carolina, USA; Antoinette
Kome, SNV, The Netherlands; Julian Kyomuhangi, Ministry of Health, Uganda; Joe Madiath, Gram Vikas,
India; Gerardo Mogol, Ministry of Health, Philippines; Guy Norman, Water and Sanitation for the Urban Poor,
UK; Kepha Ombacho, Ministry of Health, Kenya; Andy Peal, independent consultant, UK; Susan Petterson,
School of Medicine, Grith University, Australia; Oscar Pintos, Asociación Federal de Entes Reguladores de
Agua y Saneamiento de Argentina, Argentina; Andrianaritsifa Ravaloson, Ministry of Water and Sanitation,
Madagascar; Eva Rehfuess, Center for International Health, Ludwig-Maximilians-Universität München, Germany;
Virginia Roaf, Consultant, Germany; Jan-Willem Rosenboom, the Bill & Melinda Gates Foundation, USA; Linda
Strande, EAWAG, Switzerland; Garusinge Wijesuriya, Ministry of Health, Sri Lanka.
WHO Steering Group and reviewers
Magaran Bagayoko, Communicable Diseases Cluster, Regional Oce for Africa, Republic of the Congo (Congo-
Brazzaville); Hamed Bakir, Centre for Environmental Health Action, Regional Oce for the Eastern Mediterranean,
Jordan; Sophie Boisson, Department of Public Health, Environmental and Social Determinants of Health,
Switzerland; Kaia Engesveen, Department of Nutrition for Health and Development; Shinee Enkhtsetseg,
Regional Oce for Europe; Bruce Gordon, Department of Public Health, Environmental and Social Determinants
of Health, Switzerland; Rok Ho Kim, Western Pacic Regional Oce, Philippines; Dominique Legros, Department
of Infectious Hazard Management, Switzerland; Kate Medlicott, Department of Public Health, Environmental
and Social Determinants of Health, Switzerland; Teolo Monteiro, Communicable Diseases and Environmental
Determinants of Health (CDE), Panamerican Health Organization – World Health Organization (PAHO/WHO), Peru;
Antonio Montresor, Department of Control of Neglected Tropical Diseases, Switzerland; Maria Neira, Department
of Public Health, Environmental and Social Determinants of Health, Switzerland; Payden, Regional Oce for South-
East Asia, India; Annette Prüss-Üstün, Department of Public Health, Environmental and Social Determinants of
Health, Switzerland; Oliver Schmoll, Management of Natural Resources: Water and Sanitation, WHO European
Centre for Environment and Health, Germany; Anthony Solomon, Department of Control of Neglected Tropical
Diseases, Switzerland; Yael Velleman, Department of Public Health, Environmental and Social Determinants of
Health, Switzerland; Elena Villalobos Prats, Department of Public Health, Environmental and Social Determinants
of Health, Switzerland; Astrid Wester, Department of Public Health, Environmental and Social Determinants of
Health, Switzerland.
IX
ACKNOWLEDGEMENTS
Contributors
Kelly Alexander, CARE, USA; Nicholas J. Ashbolt, School of Public Health, University of Alberta, Canada;
Robert Bos, Independent Consultant, Switzerland; Val Curtis, London School of Tropical Medicine and Hygiene,
UK; Matthew C. Freeman, Rollins School of Public Health, Emory University USA; Joshua Garn, University of
Nevada, NV USA; Emily D. Garner, Department of Civil & Environmental Engineering, Virginia Tech, Blacksburg
VA USA; Guy Hutton, UNICEF, USA; Christine Moe, Rollins School of Public Health, Emory University, USA; Amy
Pruden, Department of Civil & Environmental Engineering, Virginia Tech, Blacksburg VA USA; Lars Schoebitz,
independent consultant, Switzerland, Gloria Sclar, Rollins School of Public Health, Emory University USA; Pippa
Scott, i-San, UK.
External reviewers
Robert Chambers, Institute of Development Studies, UK; Pay Drechsel, International Water Management Institute,
Sri Lanka; Barbara Evans, Faculty of Engineering, University of Leeds, UK; Darryl Jackson, independent consultant,
Australia; Marion W. Jenkins, Center for Watershed Sciences, UC Davis, USA; Jon Lane, independent consultant, UK;
Freya Mills, Institute for Sustainable Futures, University of Technology Sydney, Australia; Eduardo Perez, USAID/
Mortenson Center in Engineering for Developing Communities, University of Colorado Boulder, USA; Jan M Stratil,
Pettenkofer School of Public Health, LMU Munich, Germany; Naomi Vernon, Institute of Development Studies, UK;
Juliet Willetts, Institute for Sustainable Futures, University of Technology Sydney, Australia.
Technical editor
Lorna Fewtrell, independent consultant, UK.
External support agencies
WHO gratefully acknowledges the nancial support provided by the Department for International Development,
United Kingdom, and the Bill and Melinda Gates Foundation for the development of these guidelines and the
Swiss Agency for International Development, the United States Agency for International Development, Agence
Française de Développement, the Directorate-General for International Cooperation of the Netherlands, the
Swedish International Development Cooperation Agency and Norwegian Agency for Development Cooperation
for their wider support to the WHO Strategy on Water, Sanitation, Hygiene and Health.
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WHO GUIDELINES ON SANITATION AND HEALTH
Acronyms and abbreviations
AMR Antimicrobial resistance
BCT Behaviour Change Technique
BOD Biochemical oxygen demand
CBS Container-based sanitation
CFU Colony forming units
CHC Community Health Club
CHAST Child Hygiene and Sanitation Training
CI Condence interval
CLTS Community-led Total Sanitation
CSO Combined sewer overow
DALY Disability-adjusted life year
DHS Demographic and Health Survey
DMS Developing Markets for Sanitation
DNA Deoxyribonucleic acid
EtD Evidence to Decision
GC Gene copies
GDG Guidelines Development Group
GRADE Grading of Recommendations, Assessment, Development and Evaluation
GRC Guidelines Review Committee
GWPP Global Water Pathogen Project
FFU focus forming units
HCF Health care facility
HIV Human immunodeciency virus
HMIS Health management information system
IDP Internally-displaced person
IEC Information, Education and Communication
ID50 Dose at which 50% of subjects would become infected; or probability of infection = 0.5
ISO International Organization for Standardization
JMP The WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene
LMICs Low- and middle-income countries
MICS Multiple Indicator Cluster Survey
MoH Ministry of Health
MPN Most Probably Number
NGO Non-governmental organization
NTDs Neglected Tropical Diseases
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ACRONYMS AND ABBREVIATIONS
O&M Operation and maintenance
PCR Polymerase chain reaction
PFU Plaque forming units
PHAST Participatory Hygiene and Sanitation Transformation
PPE Personal protective equipment
PRL Pathogen reduction level
qPCR Quantitative polymerase chain reaction
RCT Randomized controlled trial
RNA Ribonucleic acid
SaaB Sanitation as a Business
SanMark Sanitation Marketing
SDGs Sustainable Development Goals
SLTS School-led Total Sanitation
SOP Standard operating procedures
spp. Several species within a genus
STH Soil transmitted helminths
TCID Tissue culture infectious dose
TIP Trials for Improved Practice
UDT Urine diversion toilet
WASH Water, sanitation and hygiene
WHO World Health Organization
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WHO GUIDELINES ON SANITATION AND HEALTH
Executive
summary
Executive summary
Introduction and scope
Safe sanitation is essential for health, from preventing infection to improving and maintaining mental and
social well-being. The lack of safe sanitation contributes to diarrhoea, a major public health concern and a
leading cause of disease and death among children under ve years in low- and middle- income countries;
poor sanitation also contributes to several neglected tropical diseases, as well as broader adverse outcomes
such as undernutrition. Lack of access to suitable sanitation facilities is also a major cause of risks and anxiety,
especially for women and girls. For all these reasons, sanitation that prevents disease and ensures privacy and
dignity has been recognized as a basic human right.
Sanitation is dened as access to and use of facilities and services for the safe disposal of human urine and
faeces. A safe sanitation system is a system designed and used to separate human excreta from human contact
at all steps of the sanitation service chain from toilet capture and containment through emptying, transport,
treatment (in-situ or o-site) and nal disposal or end use. Safe sanitation systems must meet these requirements
in a manner consistent with human rights, while also addressing co-disposal of greywater, associated hygiene
practices and essential services required for the functioning of technologies.
The purpose of these guidelines is to promote safe sanitation systems and practices in order to promote
health. They summarize the evidence on the links between sanitation and health, provide evidence-informed
recommendations, and oer guidance for encouraging international, national and local sanitation policies and
actions that protect public health. The guidelines also seek to articulate and support the role of health and
other actors in sanitation policy and programming to help ensure that health risks are identied and managed
eectively.
The main audience for the guidelines is national and local authorities responsible for the safety of sanitation
systems and services, including policy makers, planners, implementers and those responsible for the
development, implementation and monitoring of standards and regulations. This includes health authorities and,
since sanitation is often managed outside the health sector, other agencies with responsibilities for sanitation.
The guidelines were developed in accordance with the processes set out in the WHO Handbook for Guideline
Development.
Evidence summary
The evidence reviewed in the process of developing the guidelines suggests that safe sanitation is associated with
improvements in health, including positive impacts on infectious diseases, nutrition and well-being. In general,
however, the quality of the evidence is low. This is common for environmental health research generally due
to the paucity of randomized controlled trials and the inability to blind most environmental interventions. The
evidence is also characterized by considerable heterogeneity, with some studies showing little or no eect on
health outcomes. Heterogeneity can be expected in results from studies where, as here, there was high levels
of variability in the settings, baseline conditions, types of interventions, levels of coverage and use obtained,
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EXECUTIVE SUMMARY
Executive
summary
study methods and other factors likely to impact eect sizes. Sub-optimal eects can also be expected from
shortcomings in how sanitation interventions are implemented (i.e. problems with delivery of sanitation
interventions, sometimes even leading to implementation failure).
Research needs
There is need for further research on the links between sanitation and health, and on the operation of the
sanitation service chain and optimal methods for implementation. Research gaps include strategies for
encouraging governments to prioritize, encourage and monitor sanitation; creating an enabling environment;
improving coverage and securing correct, consistent, sustained use; estimating health impacts from sanitation
interventions; improving methods for assessing presence of and exposure to sanitation-related pathogens in
the environment; preventing the discharge of faecal pathogens into the environment along all steps of the
sanitation service chain; exploring alternative designs and services, including safe emptying and management
of on-site sanitation; ensuring that proposed sanitation interventions are culturally-appropriate, respect human
rights and reect human dignity; mitigating occupational exposures; reducing adverse ecological eects;
elaborating the links between sanitation and animals and their impact on human health; and investigating the
issues around sanitation and gender.
Navigating the guidelines
The Guidelines are organized as described in the table below. The recommendations and actions required to
implement them are set out in Chapter 2 following the introduction. Chapters 3 to 5 provide technical and
institutional guidance for implementation, and Chapters 6 to 9, as well as the annexes, provide further technical
resources.
Introduction, scope and objectives Chapter 1: Introduction
Recommendations and actions Chapter 2: Recommendations and good practice actions
Implementation guidance Chapter 3: Safe sanitation systems
Chapter 4: Enabling safe sanitation service delivery
Chapter 5: Sanitation behaviour change
Technical resources Chapter 6: Excreta-related pathogens
Chapter 7: Methods
Chapter 8: Evidence on the eectiveness and implementation of sanitation interventions
Chapter 9: Research needs
Annex 1: Sanitation system factsheets
Annex 2: Glossary of sanitation terms
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WHO GUIDELINES ON SANITATION AND HEALTH
Executive
summary
Recommendations
The below recommendations are provided for action by national and local authorities.
Recommendation 1: Ensure universal access and use of toilets that safely contain excreta
1.a) Universal access to toilets that safely contain excreta and elimination of open defecation should be
prioritized by governments, ensuring that progress is equitable and in line with the principles of the
human right to water and sanitation.
1.b) Demand and supply of sanitation facilities and services should be addressed concurrently to ensure toilet
adoption and sustained use and enable scale.
1.c) Sanitation interventions should ensure coverage of entire communities with safe toilets that, as a
minimum, safely contain excreta, and address technological and behavioural barriers to use.
1.d) Shared and public toilet facilities that safely contain excreta can be promoted for households as an
incremental step when individual household facilities are not feasible.
1.e) Everyone in schools, health care facilities, workplaces and public places should have access to a safe toilet
that, as a minimum requirement, safely contains excreta.
Recommendation 2: Ensure universal access to safe systems along the entire sanitation service chain
2.a) The selection of safe sanitation systems should be context specic and respond to local physical, social
and institutional conditions.
2.b) Progressive improvements towards safe sanitation systems should be based on risk assessment and
management approaches (e.g. Sanitation Safety Planning).
2.c) Sanitation workers should be protected from occupational exposure through adequate health and safety
measures.
Recommendation 3: Sanitation should be addressed as part of locally delivered services and broader
development programmes and policies
3.a) Sanitation should be provided and managed as part of a package of locally-delivered services to increase
eciency and health impact.
3.b) Sanitation interventions should be coordinated with water and hygiene measures, as well as safe disposal
of child faeces and management of domestic animals and their excreta to maximize the health benets
of sanitation.
Recommendation 4: The health sector should fulfill core functions to ensure safe sanitation to protect
public health
4.a) Health authorities should contribute to overall coordination of multiple sectors on development of
sanitation approaches and programmes, and sanitation investment.
4.b) Health authorities must contribute to the development of sanitation norms and standards.
4.c) Sanitation should be included in all health policies where sanitation is needed for primary prevention, to
enable coordination and integration into health programmes.
4.d) Sanitation should be included within health surveillance systems to ensure targeting to high disease
burden settings, and to support outbreak prevention eorts.
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EXECUTIVE SUMMARY
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4.e) Sanitation promotion and monitoring should be included within health services to maximize and sustain
health impact.
4.f) Health authorities should full their responsibility to ensure access to safe sanitation in healthcare facilities
for patients, sta and carers, and to protect nearby communities from exposure to untreated wastewater
and faecal sludge.
Good practice actions for enabling safe sanitation service delivery
The recommendations are complemented by a set of good practice actions to help all stakeholders put the
recommendations into eect.
1. Dene government-led multi-sectoral sanitation policies, planning processes and coordination.
2. Ensure health risk management is properly reected in sanitation legislation, regulations and standards.
3. Sustain the engagement of the health sector in sanitation through dedicated stang and resourcing, and
through action on sanitation within health services.
4. Undertake local health-based risk assessment to prioritize improvements and manage system performance.
5. Enable marketing of sanitation services and develop sanitation services and business models.
Principles for implementation of sanitation interventions
Safe sanitation systems
Sanitation systems should address the following minimum requirements to ensure safety along each step of
the sanitation service chain.
Toilet
• Toilet design, construction, management and use should ensure that users are safely separated from excreta.
• The toilet slab and pan or pedestal should be constructed using durable material that can be easily cleaned.
• The toilet superstructure needs to prevent the intrusion of rainwater, stormwater runo, animals and insects.
It should provide safety and privacy with lockable doors for shared or public toilets.
• Toilet design should include provision of culturally- and context-appropriate facilities for anal cleansing,
handwashing and menstrual hygiene management.
• Toilets need to be well maintained and regularly cleaned.
Containment – storage/treatment
• Where groundwater is used as a drinking-water source, a risk assessment should ensure that there is sucient
vertical and horizontal distance between the base of a permeable container, soak pit or leach eld and the
local water table and/or drinking-water source (allowing at least 15 m horizontal distance and 1.5 m vertical
distance between permeable containers and drinking-water sources is suggested as a rule of thumb).
• When any tank or pit is tted with an outlet, this should discharge to a soak pit, leach eld or piped sewer. It
should not discharge to an open drain, water body or open ground.
• Where products from storage or treatment in an on-site containment technology are handled for end use
or disposal, risk assessments should ensure workers and/or downstream consumers adopt safe operating
procedures.
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Conveyance
• Wherever possible motorized emptying and transport should be prioritized over manual emptying and
transport.
• All workers should be trained on the risks of handling wastewater and/or faecal sludge and on standard
operating procedures (SOPs).
• All workers should wear personal protective equipment (e.g. gloves, masks, hats, full overalls and enclosed
waterproof footwear) particularly where manual sewer cleaning or manual emptying is required.
Treatment
• Regardless of the source (i.e. wastewater from sewer-based technologies or faecal sludge from on-site
sanitation) both the liquid and solid fractions require treatment before end use/disposal
• The treatment facility should be designed and operated according to the specic end use/disposal objective
and operated using a risk assessment and management approach to identify, manage and monitor risk
throughout the system.
End use/disposal
• Workers handling euent or faecal sludge should be trained on the risks and on standard operating
procedures and use personal protective equipment.
• A multi-barrier approach (i.e. the use of more than one control measure as a barrier against any pathogen
hazard) should be used.
Sanitation behaviour change
Behaviour change is an important aspect of all sanitation programmes and underpins adoption and use of safe
sanitation.
• Governments are the critical stakeholder in the coordination and integration of sanitation behaviour change
activities and they should provide leadership and adequate funding.
• All sanitation interventions should include a robust sanitation promotion/behaviour change programme
(including monitoring and evaluation), with all stakeholders and participants aligned around the same set
of objectives and strategies.
• To inuence behaviour and design successful promotion activities it is important to understand the existing
sanitation behaviours and the determinants of those behaviours, noting that specic population groups will
have dierent sanitation needs, opportunities for change and barriers to improvement.
• Behaviour change interventions are most successful when they target the determinants of behaviours; a
range of models and frameworks exist to aid understanding and target behavioural drivers and should be
drawn upon in the intervention design process.
• Careful consideration should be given to the intervention delivery model (stand-alone behaviour change
versus integrated approaches; focused versus comprehensive strategies); for a strategy to be successful it
needs to impact on uptake, adherence and long-term practice/use of the safe behaviour.
• Behaviour change programming needs adequate and dedicated resources.
1
CHAPTER 1. INTRODUCTION
Chapter 1
1.1 e signicance of sanitation for
human health
Safe sanitation is essential for health, from preventing
infection to improving and maintaining mental and
social well-being. The lack of safe sanitation systems
leads to infection and disease, including:
• Diarrhoea, a major public health concern and
a leading cause of disease and death among
children under five years in low- and middle-
income countries (Prüss-Üstün et al. 2016);
• Neglected tropical diseases such as soil-transmitted
helminth infections, schistosomiasis and trachoma
that cause a signicant burden globally (WHO,
2017); and
• Vector-borne diseases such as West Nile Virus or
lymphatic lariasis (Curtis et al., 2002; van den
Berg, Kelly-Hope & Lindsay, 2013), through poor
sanitation facilitating the proliferation of Culex
mosquitos.
Unsanitary conditions have been linked with
stunting (Danaei et al., 2016), which aects almost
one quarter of children under-ve globally (UNICEF/
WHO/World Bank, 2018) through several mechanisms
including repeated diarrhoea (Richard et al., 2013),
helminth infections (Ziegelbauer et al., 2012) and
environmental enteric dysfunction (Humphrey, 2009;
Keusch et al., 2014; Crane et al., 2015) (see Box 1.1).
The lack of safe sanitation systems contributes to the
emergence and spread of antimicrobial resistance
by increasing the risk of infectious diseases (Holmes
et al., 2016) and thereby use of antibiotics to tackle
preventable infections. Inadequate management
of faecal waste that includes antimicrobial residues
from communities and health care settings can also
contribute to emergence of resistance (Korzeniewska
et al., 2013; Varela et al., 2013).
Box 1.1 Sanitation and complex health outcomes: environmental enteric dysfunction
Environmental enteric dysfunction (EED) is an acquired subclinical disorder of the small intestine, characterized by chronic inammation and
subsequent changes to the gut (such as villous atrophy and crypt hyperplasia) (Crane et al., 2015; Harper et al., 2018), potentially leading to
stunted growth and reduced response to enteric vaccines (Iqbal et al., 2018; Marie et al., 2018). The condition has been hypothesized to be an
important cause of childhood stunting in low-income settings through nutrient malabsorption, gut permeability, and chronic immune activation
that reallocates resources normally directed toward child growth and development (Harper et al., 2018; Marie et al., 2018). It is also thought to
aect brain development, with further implications for cognitive function and educational achievement (Oriá et al., 2016; Harper et al., 2018).
Although the causes of EED are dicult to describe precisely, it is assumed to be caused by exposure to bacteria from faecal contamination due
to inadequate sanitation behaviours and unsafe sanitation systems (Harper at al., 2018). High levels of undernutrition and diarrhoea in a given
population, also related to poor sanitation, are assumed to increase the likelihood of EED (Crane et al., 2015). The potential signicance of EED to
child health and nutrition, and subsequently other important health outcomes (see Table 1.1) merits greater attention in public sanitation and
health policy and programming. However, the continuous and asymptomatic nature of EED, the uncertainty surrounding its causes, prevention
and treatment (Crane et al., 2015), and the methodological and ethical challenges associated with its accurate measurement (Harper et al., 2018;
Marie et al., 2018), contribute to EED being a persistent blindspot in nutrition and health programmes.
Chapter 1
INTRODUCTION
2
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 1
Safe sanitation in health centres is an essential
component of quality of care and infection
prevention and control strategies, especially for
preventing exposure of health service users and
sta to infections (WHO, 2016a), and particularly at
protecting pregnant women and new-borns from
infections which may lead to adverse pregnancy
outcomes, sepsis and mortality (Benova, Cumming
& Campbell, 2014; Padhi et al., 2015; Campbell et al.,
2015). Access to safe sanitation systems in homes,
schools, work places, health centres, public spaces
and other institutional settings (such as prisons and
refugee camps) – is essential for overall well-being,
for example through reducing the risks (Winter &
Barchi, 2016; Jadhav, Weitzman & Smith-Greenaway,
2016) and anxiety caused by embarrassment
and shame (e.g. Hirve et al., 2015; Sahoo et al.,
2015;) associated with open defecation or shared
Direct impact (infections) Sequelae
(conditions caused by preceding infection)
Broader well-being
Faecal-oral infections
• Diarrhoeas (incl. cholera)
• Dysenteries
• Poliomyelitis
• Typhoid
Helminth infections
• Ascariasis
• Trichuriasis
• Hookworm infection
• Cysticercosis (Taenia solium/ infection)
• Schistosomiasis
• Foodborne trematodes
Insect vector diseases
(vectors breed in faeces or faecally-
contaminated water)
• Lymphatic lariasis
• West Nile Fever
• Trachoma
Stunting/ growth faltering
(related to repeated diarrhea, helminth
infections, environmental enteric dysfunction)
Consequences of stunting
(obstructed labour, low birthweight)
Impaired cognitive function
Pneumonia (related to repeated diarrhea in
undernourished children)
Anaemia (related to hookworm infections)
Immediate:
Anxiety (shame and embarrassment
from open defecation, shared sanitation) and
related consequences and not meeting gender
specic needs
Sexual assault (and related consequences)
Adverse birth outcomes
(due to underuse of healthcare facilities
with inadequate sanitation)
Long-term:
School absence
Poverty
Decreased economic productivity
Anti-microbial resistance
Table 1.1 The health impact of unsafe sanitation
Collated from: Bartram & Cairncross, 2010; Bouzid et al, 2018; Campbell et al, 2015; Cumming & Cairncross, 2016; Cairncross et al., 2013; Schlaudecker et al, 2011.
sanitation. Table 1.1 summarizes the health impact
of the lack of safe sanitation systems.
1.2 Sanitation as a human
development issue
Inadequate sanitation systems exist in many parts
of the world. Many people worldwide practice open
defecation and many more do not have services
that prevent faecal waste from contaminating
the environment (WHO-UNICEF, 2017). In many
low- and middle-income countries (LMICs), rural
areas are underserved, cities are struggling to cope
with the scale of sanitation needs caused by rapid
urbanization, while sanitation system maintenance
is challenging and costly worldwide. Challenges
caused by climate change require continued
adaptation to ensure sanitation systems safeguard
public health.
3
CHAPTER 1. INTRODUCTION
Chapter 1
Box 1.2 Human right to sanitation (UN, 2015a)
The human right to sanitation entitles everyone to sanitation services that provide privacy and ensure dignity, and that are physically accessible
and aordable, safe, hygienic, secure, socially and culturally acceptable. Human rights principles must be applied in the context of realising all
human rights, including the human right to sanitation:
1. Non-discrimination and equality: All people must be able to access adequate sanitation services, without discrimination, prioritizing the
most vulnerable and disadvantaged individuals and groups.
2. Participation: Everyone must be able to participate in decisions relating to their access to sanitation without discrimination.
3. The right to information: Information relating to access to sanitation, including planned programmes and projects must be freely available
to those who will be aected, in relevant languages and through appropriate media.
4. Accountability (monitoring and access to justice): States must be able to be held to account for any failure to ensure access to sanitation,
and access (and lack of access) must be monitored.
5. Sustainability: Access to sanitation must be nancially and physically sustainable, including in the long-term.
The normative content of the human right to sanitation is dened by:
1. Availability: A sucient number of sanitation facilities must be available for all individuals.
2. Accessibility: Sanitation services must be accessible to everyone within, or in the immediate vicinity, of household, health and educational
institution, public institutions and places and workplace. Physical security must not be threatened when accessing facilities.
3. Quality: Sanitation facilities must be hygienically and technically safe to use. To ensure good hygiene, access to water for cleansing and
handwashing at critical times is essential.
4. Aordability: The price of sanitation and services must be aordable for all without compromising the ability to pay for other essential
necessities guaranteed by human rights such as water, food, housing and health care.
5. Acceptability: Services, in particular sanitation facilities, have to be culturally acceptable. This will often require gender-specic facilities,
constructed to ensure privacy and dignity.
All human rights are interlinked and mutually reinforcing, and no human right takes precedence over another.
Box 1.3 The Sustainable Development Goals (SDGs) and sanitation (UN, 2015b)
The SDGs provide a global framework for ending poverty, protecting the environment and ensuring shared prosperity. Goal 6 on clean water
and sanitation (specically targets 6.2 and 6.3 on sanitation and water quality respectively), and Goal 3 on good health and well-being, are
particularly relevant to sanitation. Several other goals for which sanitation contributes or is necessary for achievement, including those on poverty
(particularly 1.4 on access to basic services), nutrition, education, gender equality, economic growth, reduction in inequalities and sustainable
cities. The SDGs also set out the principles of implementation for States to follow, including increasing nancing, strengthening capacity of health
workers, introduction of risk-reduction strategies, building on international cooperation and participation of local communities. Goal 1 states
the need to improve the ow of information and increase monitoring capacities and disaggregation so that it is possible to identify which groups
are being left behind.
Sanitation has gained importance on the global
development agenda, starting in 2008 with the UN
International Year of Sanitation, followed by the
recognition of sanitation as a human right (with
water in 2010, and as a standalone right in 2015)
(Box 1.2) and the call for an end to open defecation
by the UN Deputy Secretary-General in 2013. Safe
management of sanitation, as well as treatment and
reuse of wastewater, was given a central place under
the Sustainable Development Goals (SDGs) (Box 1.3).
4
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 1
1.3 Scope
These guidelines are concerned with ensuring that
sanitation systems are designed and managed
safely to protect human health from microbial
hazards caused by human excreta, and consequent
adverse health outcomes such as infectious disease,
nutritional status and educational outcomes. The
guidelines also cover well-being and psychosocial
dimensions of health (such as privacy, safety and
dignity) needed to encourage and sustain use of
sanitation services.
While animal faeces contain pathogens that can
cause disease in humans these guidelines do not
cover management of animal waste. The guidelines
cover solid waste associated with menstrual hygiene
management but do not cover other types of solid
waste, although the management of solid waste is
sometimes included in the denition of sanitation
and is also of signicance for public health.
1.3.1 Rationale for scope
The primary purpose of safe sanitation services from
a public health perspective is to full the human right
to sanitation and ensure sanitation services separate
human excreta (faeces and urine) from human contact
to interrupt pathogen transmission. Figure 1.1 shows
the transmission pathways of excreta-related infections
from left to right. Excreta enters the sanitation chain,
The commonly-used F-diagram on faecal-oral disease transmission (various versions adapted from Wagner and Lanoix, 1958) is not used in these guidelines, although several of its elements
can be clearly discerned (human hosts, and the elements described as “hazardous events” in this diagram). The purpose of this gure is to highlight the role of safe sanitation systems as
a primary barrier to transmission by showing the way in which unsafe management at each step of the sanitation chain spreads excreta in the environment; additionally, the diagram
captures transmission routes that are not faecal-oral and shows the complex ways in which dierent hazards and hazardous events interrelate. The diagram forms a conceptual basis for
risk assessment and management for sanitation systems.
Human host
Sanitation hazards Hazardous events Exposure
Disease outcome
(See table 1.1)
Faeces
Urine
Face
Mouth
Feet
Feet/skin
Fingers
Water
consumption/use
Animals*
Water
bodies/drains
Unsafe
(or non-existing/unused)
toilets
Unsafe end
use/disposal
Unsafe o site
treatment
Unsafe
conveyance/
transportation
Unsafe
containment
(storage/treatment)
Flies
Crops/food
Objects/oors/
surfaces
Ground
water
Fields
Figure 1.1 Transmission of excreta-related pathogens
5
CHAPTER 1. INTRODUCTION
Chapter 1
where sanitation hazards translate to hazardous
events through which excreta enter the environment
and expose new hosts. “Unsafe toilet” includes open
defecation and inconsistent use. The diagram allows
both vertical and horizontal interaction: horizontally,
all hazards have the potential to lead to eventual
exposure through most pathways (or “hazardous
events”); within the vertical blocks of “sanitation
hazards” and “hazardous events”, interactions can occur
across all elements (e.g. animals can spread human
excreta to elds and water bodies, as well as oors and
surfaces within homes).
Sanitation is dened as access to and use of facilities
and services for the safe disposal of human urine
and faeces. A safe sanitation system is defined
as a system that separates human excreta from
human contact at all steps of the sanitation service
chain from toilet capture and containment through
emptying, transport, treatment (in-situ or o-site) and
nal disposal or end use (Figure 1.2). Safe sanitation
systems must meet these requirements in a manner
consistent with human rights, while also addressing
co-disposal of greywater (water generated from the
household, but not from toilets), associated hygiene
practices (e.g. managing anal cleansing materials)
and essential services required for the functioning
of technologies (e.g. ush water to move excreta
through sewers).
Figure 1.2 Sanitation service chain
End use/disposalToilet
Containment–
storage/treatment
Conveyance Treatment
Read from left to right, the diagram illustrates the potential pathogen transmission pathways from a human host leading to disease outcomes, from excretion, to hazards at each step of the
sanitation service chain, to hazardous events and exposure of a new host; examples of these pathways include :
• Unsafe/ non-existing (or not used) toilets: open defecation can lead to pathogens discharged on to elds, infecting new hosts through feet or crops (e.g. soil-transmitted helminths);
into water bodies, infecting new hosts through water contact (e.g. schistosomiasis from urination/ defecation in surface water) or consumption; and overall spread within the household
environment by insects or animals acting as mechanical vectors. Poorly-constructed pit toilets can lead to ies and other insects breeding in excreta or spreading faecal pathogens to food,
ngers and surfaces.
• Unsafe containment (storage/ treatment): poor containment such as poorly-constructed latrine pits or septic tanks can cause leakage into ground water and thereby into water consumed
by new hosts; and to overow into the household environment.
• Unsafe conveyance/transportation: poor emptying practices can lead to direct exposure of sanitation workers or others involved in emptying activities to pathogens, as well as discharge of
pathogens onto household surfaces and therefore exposure through contaminated surfaces; untreated excreta discharged into water bodies, drains elds and other surfaces can potentially
lead to transmission through all types of hazardous events; and unsafe sewers can cause exposure through leakage, overow and unsafe discharge into drains, water bodies, ground water
and open surfaces.
• Unsafe o-site treatment: inadequate treatment can lead to insucient pathogen removal from faecal sludge, leading to pathogen discharge onto elds (through fertilization) and therefore
crops, and into water bodies through runo or by purposeful discharge, contaminating water for human consumption. Poorly-managed treatment processes can also allow animal contact
with untreated excreta, contributing to further exposure
• Unsafe end use/ disposal: discharge of untreated faecal sludge into the environment can lead to all hazardous events through multiple pathways.
The diagram may be read both horizontally and vertically, taking into account the potential interaction between dierent hazardous events to form complex or indirect pathways. For instance,
as well as carrying pathogens to ngers and surfaces, animals may also introduce pathogens to elds and water bodies, thereby indirectly transmitting pathogens to a new host; untreated
excreta discharged to elds may lead to contamination of ground water or water bodies; and ngers contaminated during toilet use or from contact with animals or contaminated surfaces
can transmit pathogens to food during cooking or eating, or contaminate other surfaces.
* Refers to animals as mechanical vectors. Transmission of animal excreta-related pathogens to human hosts is not represented in this diagram.
6
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 1
1.4 Objectives
The purpose of these guidelines is to promote
safe sanitation systems and practices in order to
promote health. They summarize the evidence on
the links between sanitation and health, provide
evidence-informed recommendations, and offer
guidance for encouraging international, national
and local sanitation policies and actions that
protect public health. The guidelines also seek to
articulate and support the role of health and other
actors in sanitation policy and programming to help
ensure that health risks are identied and managed
effectively. The guidelines are designed to be
adapted to local contexts taking social, economic,
environmental and health aspects into consideration.
The guidelines are relevant everywhere, especially in
LMICs where sanitation is most challenging.
Sanitation measures to protect public health are
both single- and multi-component, and include
technologies (Chapter 3), policies, regulations and
nancial and personnel resources (Chapter 4), and
sanitation behaviour change (Chapter 5). Sanitation
measures may target domestic, institutional and
commercial premises, including households, schools,
healthcare centres and other institutions (such as
prisons), as well as work places and all other toilet
facilities in public settings. They may be implemented
at local, regional, national or international levels,
through the health sector or other sectors.
The guidelines cover incremental approaches to
achieve:
1. universal coverage of and access to sanitation
2. increased quality of sanitation services and access
to higher levels of sanitation services
3. sustainability in terms of sustained functioning of
sanitation services, as well as environmental and
social sustainability.
All WHO water and sanitation related guidelines
are underpinned by the Stockholm framework and
its underlying principles of risk assessment and
management (Fewtrell & Bartram, 2001). These
principles rest on the systematic identification,
Box 1.4 Why are guidelines on sanitation and health needed?
Evaluations of sanitation interventions have shown lower than expected health outcomes, leading to concerns on the quality of implementation of
sanitation interventions and programmes. Comprehensive guidelines are needed that consider the full sanitation service chain and its implications
for human health, as well as the roles and responsibilities of health actors in securing sanitation-related health gains.
These guidelines build on previous WHO publications, starting from ‘Excreta disposal for rural areas and small communities’ (Wagner & Lanoix,
1958), and subsequent sanitation-related publications, including:
• A guide to the development of on-site sanitation (WHO, 1992);
• Guidelines for safe use of wastewater, excreta and greywater (third edition), with four volumes covering: Policy and regulatory aspects,
Wastewater use in agriculture, Wastewater and excreta use in aquaculture and Excreta and greywater use in agriculture (WHO, 2006a);
• Several guidance documents for specic settings such as:
– health care settings (Essential environmental health standards in health care, WHO, 2008);
– schools (Water, sanitation and hygiene standards for schools in low-cost settings, WHO, 2009a);
– aviation (Guide to hygiene and sanitation in aviation, third edition, WHO, 2009b); and
– ships (Guide to ship sanitation (third edition): Global reference on health requirements for ship construction and operation. WHO, 2011a).
Other publications provide guidance on related water, sanitation and hygiene topics including drinking-water quality (Guidelines for drinking-
water quality, fourth edition, WHO, 2011b); recreational water (Guidelines for safe recreational water environments, WHO, 2003 and 2006b); and
surface water (Protecting surface water for health: Identifying, assessing and managing drinking-water quality risks in surface-water catchments,
WHO 2016b).
7
CHAPTER 1. INTRODUCTION
Chapter 1
prioritization and management of health risks
throughout the system. For sanitation this means
the service chain from excreta generation to nal
disposal or reuse (Figure 1.2). This ensures that
control measures target the greatest health risks
and emphasizes incremental improvement over time.
While the Stockholm framework has been articulated
with health-based targets expressed as numerical
targets in other guidelines, a more exible approach
to risk assessment and management is reflected
in this document. Related normative guidance
documents are outlined in Box 1.4.
1.5 Target audiences
The main audience for the guidelines is national
and local authorities responsible for the safety
of sanitation systems and services, including
policy makers, planners, implementers and those
responsible for the development, implementation
and monitoring of standards and regulations. This
includes health authorities and, since sanitation
is often managed outside the health sector, other
agencies with responsibilities for sanitation.
Within the Ministry of Health, this document is
relevant for sta from departments of environmental
health and from other health programmes seeking
guidance on sanitation interventions in the context
of disease prevention and control strategies.
International organizations, funding agencies, non-
governmental organizations (NGOs), civil society,
academia and others working on sanitation across
multiple sectors will also have an interest in these
guidelines when developing and contextualizing
strategies, programmes and tools for sanitation
measures to ensure they protect public health.
At their broadest application the guidelines are a
general reference on sanitation and health.
1.6 Health authorities mandate
Health sector engagement and oversight are essential
to ensure that sanitation policies and programmes
effectively and sustainably protect public health
(Rehfuess et al., 2009; Mara et al., 2010). The health
sector’s mandate includes the following functions
(detailed further in Chapter 4):
• Sanitation coordination
• Health in sanitation policies
• Health protecting norms and standards
• Health surveillance and response
• Sanitation in health programme delivery
• Sanitation behaviour change
• Healthcare facilities
1.7 Methods
These guidelines were developed following the
procedures and methods described in the WHO
handbook for guideline development (2
nd
edition 2014)
and were reviewed by the Chair and Secretariat of
the WHO Guidelines Review Committee. Because
the nature of the recommendations was deemed
equivalent to good practice statements, they were
not formally reviewed by the Guidelines Review
Committee. The methods are discussed in more detail
in Chapter 7.
Key methodological steps covered:
1. formulating the scoping questions based on a
robust conceptual framework
2. prioritizing key questions
3. identifying and/or conducting systematic reviews
to address the key questions
4. assessing the quality of the evidence
5. formulating recommendations and good practice
actions
6. writing the guidelines and
7. developing a plan for dissemination and
implementation.
8
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 1
1.8 Guidelines structure
This document sets out the need for and purpose
of the guidelines (Chapter 1), followed by detailed
recommendations and good practice actions
(Chapter2). Detailed guidance is then provided
on all aspects of sanitation systems, particularly
those aspects underlying their health impact and
sustainability (principles and technical aspects for
safe sanitation systems (chapter 3), service delivery
(Chapter 4) and behaviours (Chapter 5)). Technical
aspects underpinning the rationale and process for
guidelines development follow in chapters 6–9 and
Annex 1.
Introduction, scope and objectives Chapter 1: Introduction
Recommendations and actions Chapter 2: Recommendations
Implementation guidance Chapter 3: Safe sanitation systems
Chapter 4: Enabling safe sanitation service delivery
Chapter 5: Sanitation behaviour change
Technical resources Chapter 6: Excreta-related pathogens
Chapter 7: Methods
Chapter 8: Evidence on the eectiveness and implementation of sanitation interventions
Chapter 9: Research needs
Annex 1: Sanitation system factsheets
Annex 2: Glossary of sanitation terms
9
CHAPTER 1. INTRODUCTION
Chapter 1
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Odisha, India. Soc Sci Med. 139: 80-89.
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Schlaudecker EP, Steinho MC, Moore SR (2011). Interactions
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United Nations (2015a). General Assembly Resolution 70/169:
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Nations, New York, USA.
United Nations (2015b). General Assembly Resolution 70/1.
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UNICEF, WHO and the World Bank (2018). Joint child malnutrition
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van den Berg H, Kelly-Hope LA, Lindsay SW (2013). Malaria and
lymphatic lariasis: the case for integrated vector management.
Lancet Infect Dis. 13(1):89-94.
Varela AR, Ferro G, Vredenburg J, Yanik M, Vieira L, Rizzo L, et
al. (2013). Vancomycin resistant enterococci: from the hospital
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Wagner EG, Lanoix JN (1958). Excreta disposal for rural areas and
small communities. Mongr Ser World Health Organ 39: 1-182.
Winter SC, Barchi F (2016). Access to sanitation and violence
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(DHS) data in Kenya. Int J Environ Health Res. 26(3): 291-305.
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of on-site sanitation. WHO, Geneva, Switzerland.
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recreational water environments. Volume 1: Coastal and fresh
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World Health Organization (2006a). Guidelines for the safe use
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World Health Organization (2008). Essential environmental
health standards in health care. WHO, Geneva, Switzerland.
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11
CHAPTER 2. RECOMMENDATIONS AND GOOD PRACTICE ACTIONS
Chapter 2
This chapter sets out recommendations for action by
governments and partners.
The recommendations are complemented by a set of
good practice actions to help all stakeholders put the
recommendations into eect.
2.1 Recommendations
Recommendation 1: Ensure universal access
and use of toilets that safely contain excreta
This recommendation is in line with human rights
principles and reinforces SDG 6 (“Ensure availability
and sustainable management of water and sanitation
for all”) and target 6.2 (“by 2030, achieve access to
adequate and equitable sanitation and hygiene for all
and end open defecation, paying special attention to
the needs of women and girls and those in vulnerable
situations”). It emphasizes the general principle that
safe sanitation systems should be available to and used
by all, starting with universal access to a safe toilet that
safely contains excreta as an essential step towards
a safe full sanitation service chain. Governments are
ultimately responsible for ensuring universal access to
toilets with a subsequent safe sanitation service chain.
1.a) Universal access to safe toilets and elimination of
open defecation should be prioritized by governments,
ensuring that progress is equitable and in line with the
principles of the human rights to water and sanitation
The principles of the human rights to water and
sanitation state that progress towards universal access
should be equitable. Universal access can only be
attained through incremental progress. A national level
risk assessment can be used to identify highest risk
populations and to target interventions to ensure no
one is left behind in national targets, policy, legislation,
resources allocation and monitoring and reporting
on progress. To ensure equitable progress, specic
eorts and resources to address the most marginalised
groups will likely be required.
Rationale and evidence:
• The human rights to water and sanitation oblige all UN
Member States to consider all aspects of access to services,
including increasing the number of people with access to at
least minimum services, improvement in levels of services,
and explicitly targeting poor, marginalised and disadvantaged
people (Committee on Economic, Social and Cultural Rights
(CESCR), 2010; UN, 2015).
• There is a relationship between inadequate sanitation and eight
dimensions of social and mental well-being – lack of privacy,
shame, anxiety, fear, assault, lack of safety, embarrassment and
lack of dignity. Privacy and safety have been identied as root
dimensions (Sclar et al., 2018).
1.b) Demand and supply of sanitation facilities and
services should be addressed concurrently to ensure
toilet adoption and sustained use and enable scale
Adoption and sustained use of sanitation facilities
requires construction of safe toilets and their sustained
use. Access to a toilet does not mean it is used or
used consistently by everyone at all times. Poorly
constructed and managed facilities may lead to
households reverting to open defecation.
Chapter 2
RECOMMENDATIONS AND
GOOD PRACTICE ACTIONS
12
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 2
Toilets should be available, accessible and aordable
to all, constantly, and at least separate excreta from
human contact. Their design should be culturally-
appropriate, suitable to locally-available materials
and physical conditions such as water availability and
ground/soil conditions, and in line with ability and
willingness to pay.
Promotion strategies may be required to ensure
sustained demand for and adoption of toilets, and
their use by the whole community, as well as relevant
practices such as safe disposal of child faeces, hand
washing with soap, and toilet cleanliness. Such
strategies must be context-specic and compatible
with human rights, and respect individuals and the
community. They should address all parts of the
community regardless of age, gender, social class
and disability. Additional approaches for increasing
sustained access and use such as subsidies and
sanitation marketing should be considered so that
increased demand for sanitation products is met. Such
approaches should be suitable and acceptable, and
implementation should include review and adaptation
to ensure their eectiveness and cost-eectiveness.
Rationale and evidence:
• Access to sanitation facilities is a pre-requisite to ending open
defecation, but it is not a sucient condition (Barnard et al.,
2013; Coey et al., 2014)
• There are several potential reasons for poor latrine use and
reversion to open defecation, including high maintenance and
repair costs, poor latrine quality and durability, lack of consistent
follow up and monitoring, and occasions in which coercive
methods have resulted in latrine construction without creating
genuine buy-in for sustained use (Venkataramanan et al. 2018)
• Multiple psychosocial (norms and nurturing), non-modiable
(age and gender) and technology (cost, durability and
maintenance) factors inuence initial and sustained adoption
of clean water and sanitation technologies (Hulland et al. 2015).
1.c) Sanitation interventions should ensure coverage of
entire communities with safe toilets that, as a minimum,
safely contain excreta, and address technological and
behavioural barriers to use
Access and use of safe toilets by the entire community
is needed to achieve health gains from sanitation.
Without community level coverage, those using safe
toilets remain at risk from unsafe sanitation systems
and practices by other households, communities
and institutions. Therefore, interventions should
ensure consistent use of toilets by everyone in the
community. In urban areas, achieving full coverage
and safe containment is also important and should
be addressed through city-wide planning and
implementation, as interlinkages can occur through
waterways, groundwater, pipes and drains.
In addition, a minimum quality of toilet and
containment – storage/treatment is needed to
sustain use, to prevent excreta contaminating the
local environment and to allow for connection
to a safe sanitation chain (recommendation 2).
Interventions to end open defecation should not
promote the adoption of facilities that inadvertently
increase exposure of users to faecal pathogens or
cause users to revert to open defecation due to poor
quality, inaccessibility, or breakdown of the toilet.
Interventions should therefore ensure use of at least
safe toilets and safe containment – storage/treatment
by the entire community. Barriers to community
toilet access and use should be addressed, including
structural barriers (e.g. inappropriate or failed design,
poor quality construction and operation, full pits, lack
of privacy, lack of water) and behavioural barriers
(e.g. cultural or societal preferences, locked facilities
at night, burden of maintenance, uncertainty about
pit lling and/or emptying).
13
CHAPTER 2. RECOMMENDATIONS AND GOOD PRACTICE ACTIONS
Chapter 2
Communities should be at the centre of the sanitation
development process in terms of design, placement,
features and amenities and systems for operation
and maintenance, considering preferences, priorities,
ability to pay, gender needs, and religious and cultural
practices. Communities may not be homogenous,
especially in urban areas, and preferences and needs
may dier among households and individuals.
Rationale and evidence:
• Absence of open defecation is associated with healthier
populations in terms of reduced incidence or prevalence
of infectious disease (Freeman et al., 2017; Majorin et al.,
2017; Speich et al., 2016; Yates et al., 2015), nutritional status
(Freeman et al., 2017), cognitive development (Sclar et al.,
2017) and general well-being, particularly for women and girls
(Sclar et al., 2018; Caruso et al., 2017a & b).
• Health gains are associated with community coverage and use
exceeding certain possibly location-specic levels (Garn et al.,
2017; Oswald et al., 2017; Fuller et al. 2016).
• Behavioural barriers to use include cultural or societal
preferences, locked facilities at night, burden of maintenance,
uncertainty about pit lling and/or emptying (Garn et al., 2017;
Nakagiri et al., 2016; Routray et al., 2015).
• Barriers are likely to be context specic (Coey, Spears & Vyas,
2017; Novotný, Hasman & Lepič, 2017).
1.d) Shared and public toilet facilities that safely
contain excreta can be promoted for households as an
incremental step when individual household facilities
are not feasible
It may not be possible in the short term to cover entire
communities with safe household toilets. Factors that
limit household level access include insecure land
tenure and insucient space for toilets, containment
and conveyance, and emergency situations. Under
these circumstances, shared or public toilets that safely
contain excreta (Chapter 3.2 and 3.3) may be promoted
for households as an incremental step to ensure
everyone has access to a safe toilet and all excreta is
contained at the community level. Shared facilities
are only acceptable when they meet the standards
for accessibility, safety, hygiene, maintenance and
affordability described in Chapter 3.2.2) and user
acceptability is prioritized in sanitation promotion
strategies.
Rationale and evidence:
• Sharing a sanitation facility with more than one household
is associated with increased risk of adverse health outcomes
compared to private household facilities, including increased
odds of moderate to severe diarrhoea in children <5 years
(Heijnen et al. 2014, Baker et al., 2016). However, the additional
risk associated with latrine sharing between several households
may be attributed to dierences in user demographics, access,
type of facilities and cleanliness.
• Public and shared sanitation in urban settlements has been
linked to stress from lack of cleanliness, anxiety and withholding
relief due to long lines, women’s and girls’ fear of harassment
from men and boys, and lack of privacy or safety (Sclar et al.,
2018).
• Homeless, itinerant and slum dweller populations are forced
to openly defecate when public facilities are broken, unclean,
too far away or have long queues preventing individuals from
working or attending to childcare. This highlights the need
for a shared sanitation policy that addresses maintenance,
accessibility, cleanliness and provision of water and hand
washing facilities (Heijnen et al., 2015; Rheinländer al., 2015;
Alam et al., 2017).
• Shared sanitation can represent an important advantage over
open defecation or unsafe sanitation when individual household
facilities are not yet in place or are infeasible (Heijnen et al.,
2014, 2015).
1.e) Everyone in schools, health care facilities,
workplaces and public places should have access to
a safe toilet that, as a minimum requirement, safely
contains excreta
Universal access implies that toilets are accessible in
all aspects of daily life including at home, at school,
in healthcare settings, workplaces and public places
such as markets and transportation facilities for the
entire population.
All toilets in schools, health care facilities, workplaces
and public places should meet the standards for a safe
toilet and safe containment, paying special attention
to the need for availability, accessibility, privacy and
security and menstrual hygiene management (Chapter
3.2 and 3.3).
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WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 2
Rationale and evidence:
• Safe sanitation in health centres is an essential component of
quality of care and infection prevention and control strategies,
especially for preventing exposure of health service users and
sta to infections (WHO, 2008; WHO, 2016), and particularly at
protecting pregnant women and new-borns from infections
which may lead to adverse pregnancy outcomes, sepsis and
mortality (Benova, Cumming & Campbell, 2014; Padhi et al.
2015; Campbell et al., 2015).
• Improved sanitation conditions in schools potentially aect child
health and well-being (UNICEF, 2012)
• Sanitation provision in businesses and workplaces can
contribute to improving gender equity, increasing productivity
and reducing absenteeism (Kiendrebeogo, 2012; WSSCC and UN
Women, 2014; WSUP, 2015).
Recommendation 2: Ensure universal access to
safe systems along the entire sanitation service
chain
Universal access and use of safe toilets that contain
excreta (Recommendation 1) is a rst step towards
health-protective sanitation systems and services.
This recommendation area covers safe sanitation
systems beyond the toilet and containment step. A
safe sanitation chain is needed to realise substantive
impact on sanitation-related disease. Sanitation
systems should address containment, emptying,
conveyance, treatment and end use or disposal of
excreta, to achieve safe sanitation.
This recommendation area highlights the need to
ensure systems and services are selected to respond
to the local context and that investment and
system management are based on local level risk
assessments along the entire sanitation chain (e.g.
Sanitation Safety Planning) to ensure users and the
community are protected. In addition, it recognizes
the need for protection of sanitation workers through
safe working conditions.
Selection of sanitation systems should be context-
specific, responding to physical, social and
institutional conditions.
2.a) The selection of safe sanitation systems should be
context specific and respond to local physical, social and
institutional conditions
No single type of sanitation system is ideal in all
settings. Sanitation systems must be context specic,
evolving over time and taking into consideration
population density, hydrological conditions (e.g.
potential for groundwater contamination), life cycle
cost and nancing options, capacity for installation,
operation and maintenance, and disposal/
reuse options. The design and implementation
process should incorporate extensive stakeholder
consultation, which includes the local community.
Well-managed and well-used on-site sanitation, for
example, can eectively reduce exposure to excreta,
and represents a low-cost option in resource-
constrained settings where safe sewer solutions are
prohibitively costly. It should be recognized that typical
on-site septic tanks provide only primary treatment,
and therefore pathogen removal from sludge and
euent is low. When not functioning properly, on-
site sanitation systems may lead to unsafe discharge
of excreta into the environment, for instance through
release to drains. Decentralised or small-scale systems
are also available, and well-designed and maintained
sewer systems oer a popular and eective means
of addressing the full sanitation chain, especially in
urban and other high population density settings,
yet they have higher capital and operating costs and
can cause excreta exposure if sewage ows through
open drains, or is not eectively treated, and if there
are leaks; additionally, large scale sewer systems are
generally less resilient to the impact of climate change.
15
CHAPTER 2. RECOMMENDATIONS AND GOOD PRACTICE ACTIONS
Chapter 2
Rationale and evidence:
• The importance of the social, institutional and physical
context for the successful implementation and sustainability
of sanitation technologies and interventions is increasingly
acknowledged in sanitation planning (Ingallinella, 2002;
Overbo et al., 2016; Mills et al., 2018).
• In their seminal book on faecal sludge management, Strande
et al (2014) set out the necessary conditions for the successful
implementation of technologies and system options, including
soil conditions, climate and population density, as well as the
importance of operation and maintenance. Among the success
factors for the implementation of institutional frameworks for
faecal sludge management, they include political prioritization,
coordination, holistic response to entire areas and populations,
nancial, environmental and social sustainability, and capacity
for monitoring, operation and maintenance and financial
management, among others.
• Water supplies may become contaminated with faecal
pathogens from pit latrines, sewage pipes and poor sewage
treatment systems (Williams et al., 2015). The impact of latrines
and septic systems on groundwater quality is dependent on soil
type, distance between groundwater and pit or drain eld, and
hydrological conditions. Seasonal eects on well contamination
in areas with a high density of latrines or septic systems have
also been reported.
• There is an inverse relationship between the distance of a water
supply from a latrine and risk or level of faecal contamination
of the same water supply, although the eects may not only
depend on distance but also seasonality and latrine density
(Sclar et al., 2016).
2.b) Progressive improvements towards safe sanitation
systems should be based on risk assessment and
management approaches
It may take many years and long- term investment to
achieve universal access to safe sanitation systems.
A locally-specic risk assessment and management
approach can identify (e.g. Sanitation Safety
Planning) incremental improvements at each step
of the sanitation service chain to allow progressive
implementation towards sanitation targets and
allows investment to be prioritized according to the
highest health risk and thereby maximize gains.
The risk assessment should account for hazards
associated with normal conditions as well as variability
of the population, seasons and climate change, and
should assess potential exposure and risks to all groups
along the chain – users, local communities, workers
and wider communities. When considering new
controls, it should assess the eectiveness of existing
controls and introduce a combination of technical (e.g.
improved containment or conveyance infrastructure),
management (e.g. appropriate regulations) and
behavioural interventions (e.g. to improve service
provider or user practices) to manage risks.
Rationale and evidence:
• The Stockholm Framework provides the theoretical risk
assessment and management framework that underpins all
WHO guidance on managing health risks associated with water
and sanitation (Fewtrell & Bartram, 2001).
• Where systems lack integrity at any point, leakage of excreta
may occur, providing opportunities for human exposure (Sclar
et al., 2016) and potential infection with a range of faecal
pathogens (e.g. Freeman et al., 2017, Speich et al., 2015, Mills
et al., 2018).
2.c) Sanitation workers should be protected from
occupational exposure through adequate health and
safety measures
Sanitation workers are typically at high risk from
faecal pathogens in their daily work through handling
of faecal sludge and wastewater and equipment used
in emptying, conveyance and treatment of faecal
sludge and wastewater, work in conned spaces,
proximity to aerosols created by treatment processes,
and cuts and abrasions from co-disposed solid waste.
They are also exposed to other chemical and physical
risks from use of hazardous cleaning agents and
heavy labour.
Occupational health risks should be included in
the risk assessment and management approach
(recommendation 2b) and protection should be
provided to workers by formal sanitation service
providers. Technical protection measures such as
phasing out manual emptying and replacing it with
16
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 2
motorized systems should be combined with other
measures such as appropriate personal protective
equipment, standard operating procedures and
regular health checks and necessary prophylactic or
responsive treatments.
Rationale and evidence:
• Manual desludging poses the greatest risk from faecal
pathogens (Thye, Templeton & Ali, 2011; Eales, 2005)
• Sewage workers experience headaches, dizziness, fever, fatigue
and gastrointestinal symptoms (Jegglie et al., 2004; Thorn &
Kerekes, 2001; Tiwari, 2008). Other occupational health issues
include infections such as hepatitis A and leptospirosis due to
exposure to animal urine, and respiratory problems such as
asthma due to the inhalation of bacterial endotoxins (Glas, Hotz
& Steen, 2001; Thorn & Kerekes, 2001; Tiwari, 2008).
• Sanitation workers may be exposed to ‘sewer gas’ produced
during the breakdown of faecal sludge, which is composed
of hydrogen sulphide, methane, nitrogen, carbon dioxide
and ammonia. This is toxic, and inhalation can have fatal
consequences (Knight & Presnell, 2005; Lin et al., 2013; Tiwari,
2008).
• The manual labour required of sanitation workers can result in
musculoskeletal disorders including back pain (Charles, Loomis
& Demissie, 2009; Tiwari, 2008).
• Sanitation workers undertaking cleaning tasks may experience
skin irritation due to persistent use of latex gloves and exposure
to cleaning agents (Brun, 2009).
Recommendation 3: Sanitation should be
addressed as part of locally delivered services
and broader development programmes and
policies
Sanitation services should be provided within the
context of a package of basic local services, for which
government is responsible and accountable, even where
services are delivered by non-government entities.
Planning and delivering sanitation services in
conjunction with other services increases eciency
of implementation, sustainability of services, and the
likelihood of improved public health outcomes.
3.a) Sanitation should be provided and managed as part
of a package of locally-delivered services to increase
efficiency and health impact
Sanitation services should be included in local
planning processes (for land use, water supply and
drainage, transport and communications and solid
waste management) to avert the higher cost and
complexity of retrofitting sanitation services and
infrastructure where there is insucient space and
where sanitation clashes with other local services
and infrastructure. Special consideration is needed
when solid waste and excreta are co-disposed at the
toilet step (eg: solid waste disposal in dry toilets, child
or adult faeces disposed in solid waste) or mixed at
the end-use and disposal steps (e.g. sludge disposal
in landll, co-composing of sludge and organic solid
waste).
Eciency can also be gained during construction by
working on multiple services at the same time, ensuring
that any development, such as road construction, is
utilized as an opportunity for expanding sanitation
services coverage, for example by concurrent
construction of sewers and drains. Eectiveness may
also be enhanced through integrated consideration
of water, stormwater and wastewater at appropriate
scales, particularly in urban areas.
Rationale and evidence:
• Inadequate links between urban sanitation planning and overall
urban planning and budgeting results in unequal progress, with
the urban poor living in slums being left behind (WaterAid
2016).
3.b) Sanitation interventions should be coordinated with
water and hygiene measures, as well as safe disposal
of child faeces and management of domestic animals
and their excreta to maximize the health benefits of
sanitation
Multiple barriers are needed to address all pathways
of faecal pathogen transmission. While sanitation is a
17
CHAPTER 2. RECOMMENDATIONS AND GOOD PRACTICE ACTIONS
Chapter 2
primary barrier, secondary barriers such as safe water,
handwashing with soap, animal waste management
and y control are needed. Interventions to address all
pathways may be delivered together in a transformative
water, sanitation and hygiene (WASH) approach or
separately, drawing on specic disciplines for safe water
supply, sanitation, hygiene and environmental health.
However, ultimately all pathways need to be addressed
to achieve signicant health gains.
Water supply: Access to adequate water supplies is
a vital part of ensuring a safe sanitation service chain
for operation (e.g. ushing, sewerage), maintenance
and cleaning of facilities and various parts of the
sanitation service chain (containers, personal
protective equipment, etc), as well as for personal
and domestic hygiene purposes. In some cultures,
water is necessary for cleansing after defecation, so its
absence may encourage open defecation near surface
water bodies. Piped water to the household can
incentivize all householders in a community to build
and use toilets, and must be available year-round to
enable this outcome. No minimum requirements are
prescribed, as these depend upon the context and
include aspects such as water availability, type of
facilities, number of users, cleansing requirements
and other local factors. These all require consideration
when designing and implementing a comprehensive
sanitation programme. All water supply for human
consumption should follow WHO Guidelines on
Drinking Water Quality (WHO, 2011).
Hand washing with soap: Handwashing with soap
after defecation and any potential contact with faeces
(for example child faeces) should be promoted and
supported by the availability of soap and water close
to sanitation facilities. In public facilities (such as
schools, health care centres, food establishments,
markets etc.) handwashing facilities should be
mandatory and included in routine inspection and
monitoring schemes.
Other environmental considerations: Sanitation
interventions should be developed considering
the full range of relevant transmission pathways
of excreta-related diseases. Specific aspects
inconsistently addressed through the sanitation
service chain include safe disposal of child faeces,
measures for y control, consideration of animals
as mechanical vectors of human faeces, and food
hygiene. Despite having a higher pathogen load
than adult faeces, child faeces are often considered
innocuous and therefore not disposed of safely
even by those with access to sanitation facilities.
Disposal of child faeces in a toilet connected to a safe
sanitation chain is the only safe method where solid
waste management systems for children’s absorbent
underclothes (nappies) disposal are not safe. Policies
encouraging the safe disposal of child faeces should
include the promotion of supporting products such
as nappies/diapers, potties and sanitary scoops
(Sultana et al., 2013) and behaviour change strategies
to overcome barriers to disposal of child faeces and
water used for child bathing after defecation. Potties,
sanitary scoops and nappies should be cleaned with
water that is safely disposed of, and non-reusable
nappies and child wipes should be properly disposed
of. Flies and animals can act as mechanical vectors
for faecal pathogens. Flies land on or breed in
exposed human faeces, including on toilet surfaces,
and transport faecal matter and pathogens onto
surfaces, food and people. Household and livestock
animals may spread faecal matter around households
and water sources, through contact with exposed
faeces and faecal sludge. Measures for reducing
these transmission pathways should be considered
alongside all other sanitation service chain aspects,
and include household waste management, removal
of animal faeces, keeping livestock away from living
quarters, and use of drying racks to reduce ies, and
restricting animals from entering household living
and cooking areas and water sources. Exposure to
excreta-related pathogens through ingestion of fresh
18
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 2
produce contaminated during growing, marketing or
household preparation is also an important exposure
pathway that needs to be addressed though food
hygiene practices in the home, as well as control
measures to achieve pathogen reductions along the
sanitation chain from toilet to table.
Rationale and evidence:
• Having a handwashing station close to toilet facilities
encourages handwashing behaviour (Aunger et al., 2010; Biran
et al., 2012). Handwashing promotion can reduce diarrhoea
by about 30% in both child day-care centres in high-income
countries and among communities in LMICs (Ejemot-Nwadiaro
et al., 2015).
• Safe disposal of child faeces remains a major challenge (Morita,
Godfrey & George, 2016; Majorin et al., 2018; Miller-Petrie et
al., 2016). Child faeces are often considered innocuous and, as
such, are not disposed of safely (Majorin et al., 2017; Rand et
al., 2015). Child faeces may have higher pathogen loads than
those of adults (Lanata et al, 1998). Even those with access
to sanitation facilities often fail to use them for disposal of
child faeces (Miller-Petrie et al., 2016; Majorin et al., 2017;
Freeman et al., 2014). In 15 out of 26 locations more than
50%of households reported that the faeces of their youngest
child under three years were disposed of unsafely (not into
a latrine); the percentage of faeces ending up in improved
sanitation facilities is even lower (Rand et al., 2015).
• Flies are mechanical vectors of a variety of enteric pathogens
including bacteria and protozoa (Cohen et al., 1991; Fotedar,
2001; Khin et al., 1989; Szostakowska et al., 2004).
• Use of wastewater in crop irrigation (as well as other sanitation
end use products in crop fertilization), can lead to adverse
health impacts through pathogen exposure, at the same time
that such use can contribute to improved food security and
nutritional outcomes (WHO, 2006).
Recommendation 4: The health sector should
fulll core functions to ensure safe sanitation
to protect public health
While implementation of sanitation programmes
is often delivered through infrastructure ministries,
agencies and utilities, the overall responsibility to
ensure these investments result in improved public
health lies with health authorities. This implies
roles that includes sanitation considerations within
all functions of the health system, including target
setting according to public health considerations,
coordination of all relevant sectors, use of sanitation
and sanitation-related epidemiological data for
decision making, standard setting and regulatory,
monitoring and accountability measures.
4.a) Health authorities should contribute to overall
coordination of multiple sectors on development of
sanitation approaches and programmes, and sanitation
investment
Coordination is required to accommodate the multi-
sectoral nature of sanitation and facilitate action
by multiple stakeholders including overall health,
education, housing, agriculture, development, public
works and environment programmes. These should
be coordinated with corresponding government
ministries and agencies when sanitation interventions
are implemented in institutional settings such as schools
and health care facilities, and with broader sectors and
industries that produce, treat or use sanitation services,
products or by-products. Institutions responsible for
water, sanitation and hygiene should collaborate with
health care authorities for implementation.
4.b) Health authorities must contribute to the
development of sanitation norms and standards
This includes contribution to the development (or
revision) and implementation of safety standards and
regulations such as minimum standards reecting the
principles of safe management of excreta at each step
of the sanitation service chain and establishing risk
assessment and management approaches along the
entire service chain.
4.c) Sanitation should be included in all health policies
where sanitation is needed for primary prevention,
to enable coordination and integration into health
programmes
This involves developing and strengthening national
public health strategies, so that they highlight the
importance of sanitation as the basis for primary
19
CHAPTER 2. RECOMMENDATIONS AND GOOD PRACTICE ACTIONS
Chapter 2
prevention and include measures to improve
sanitation by each of the responsible agencies. It
also includes the generation of evidence on the
health risks and burden related to poor sanitation,
and provision of that evidence to other ministries, to
inform investment and planning.
4.d) Sanitation should be included within health
surveillance systems to ensure targeting to high disease
burden settings, and to support outbreak prevention
efforts
Health surveillance includes the strengthening of
health management information systems (HMIS)
and making better use of epidemiological data and
risk factors for sanitation-related diseases to inform
investment and planning of sanitation interventions
and improve targeting of sanitation services to
populations with high disease burden. This includes
harmonized monitoring systems and mechanisms
to link health and sanitation data and early warning
tools to prevent and control sanitation-related
diseases.
4.e) Sanitation promotion and monitoring should be
included within health services to maximize and sustain
health impact
Sanitation promotion should be included in health
programmes designed to improve maternal and
child health, food safety and nutrition, and to prevent
vector borne, zoonotic and neglected tropical
diseases. The health sector is responsible for ensuring
that health programmes adequately reect sanitation
where relevant. This may include:
• including sanitation-related disease prevention
measures and promotional approaches in the
curricula of medical, nursing and other health
profession training certicates
• embedding sanitation in health outreach
programmes by providing frontline health workers
and/or volunteers with adequate skills, resources
and incentives to promote and monitor sanitation
practices
• embedding sanitation-related responsibilities in
the job descriptions, supervision and performance
management systems for frontline health cadres
• including sanitation-related activities in local
health budgets
Sanitation promotion is an important function
that should be embedded to the extent possible in
community-based, school-based and population-
wide initiatives and campaigns. Health authorities
should provide, directly or through procurement
of advisory services, guidance, technical expertise
and support on the design of eective approaches
to create demand for sanitation services at scale
through sanitation promotion.
4.f) Healthcare authorities should fulfil their
responsibility to ensure access to safe sanitation in
healthcare facilities for patients, staff and carers, and to
protect nearby communities from exposure to untreated
wastewater and faecal sludge
Health authorities are directly responsible for
ensuring that all healthcare facilities have adequate
sanitation systems for sta, patients and caregivers
and that there are effective procedures in place
to ensure the safe management of faecal waste.
Additionally, measures must be taken to ensure that
surrounding communities are protected from excreta
(as well as other waste) generated within healthcare
facilities. This requires adequate ongoing nancial
resources, dedicated and trained sta and regular
operation and maintenance. The WHO has provided
specic guidance on WASH in healthcare facilities
(WHO, 2008; WHO/UNICEF 2018), setting out guiding
principles and standards.
20
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 2
Rationale and evidence:
• Environmental health delivered through critical health sector
functions is essential in preventing a signicant proportion of
the burden of disease globally; these functions are: (i) ensuring
that environmental health issues are adequately reected in
inter-sectoral policy development and implementation; (ii)
setting and overseeing the implementation of health-protecting
norms and regulations; (iii) incorporating environmental health
in disease-specic and integrated health programmes; (iv)
practising environmental health in health-care facilities; (v)
preparing for and responding to outbreaks of environment-
mediated diseases; and (vi) identifying and responding to
emerging threats and opportunities for health (Rehfuess, Bruce
& Bartram, 2009).
• Successful programming outcomes for sanitation are more likely
where coordination and collaboration between dierent sectors
and stakeholders exists (Overbo et al., 2016), aecting both the
scale and eectiveness of sanitation programmes.
• Lower prevalence or incidence of disease is associated with
greater access to sanitation, particularly for diseases and
conditions that continue to inflict a heavy burden in low-
income settings including diarrhoea, soil-transmitted helminth
infections, trachoma, cholera, schistosomiasis and poor
nutritional status (Freeman et al., 2017; Speich et al., 2016).
• Sanitation plays a role in improving broader aspects of health,
including gender, security, quality of life and overall well-being
(Sclar et al., 2018).
2.2 Good practice actions
1. Define government-led multi-sectoral
sanitation policies, planning processes and
coordination
• Set targets based on situation analysis, linked to
the sustainable development agenda, to allow
incremental progress towards universal access to
safe sanitation systems and services in all settings (i.e.
households, health facilities, schools, workplaces and
public places).
• Dene sanitation as a basic service in national
and sub-national plans, for which government is
responsible and accountable.
• Review and update existing policies to identify
impediments to improving sanitation along the
whole service chain and in all settings including
linkages with related sectors such as agriculture
and urban planning.
• Dene policies and plans that:
– Prioritize groups based on risk (e.g. low
coverage, endemicity, disability, conflict,
informal settlements, ood prone areas) and in
line with human rights principles.
– Reect the needs of women and girls for security,
privacy and menstrual hygiene management.
– Are informed by research in implementation
science, technology and engineering, exposure
science, epidemiology and behaviour science.
– Use lessons from existing programmes to respond
to barriers to sanitation adoption and use and
allow implementers to tailor programmes that
address them.
– Provide the policy basis for addressing
affordability gaps and access for vulnerable
populations, including linking to social
protection policies and nancing mechanisms.
• Ocially recognize that safe sanitation systems
can be delivered through a mix of technologies,
implemented through approaches tailored to the
local context and based on sound risk assessment.
• Define roles and responsibilities for sanitation
functions avoiding gaps and overlaps and
distinguishing responsibilities for all settings.
• Establish a coordination function (e.g. a sanitation
secretariat or working group) in a senior ministry
such as planning or nance.
• Establish dedicated government budget lines
for sanitation and define mechanisms for
disbursement and reporting at all levels of
government.
• Establish accountability frameworks with targets,
clear timelines, indicators and milestones, linked
to the budget and process and covering both
government funds and external funding though
grants and loans.
• Establish a robust sanitation monitoring
mechanism at the lowest administrative level
21
CHAPTER 2. RECOMMENDATIONS AND GOOD PRACTICE ACTIONS
Chapter 2
under the responsibility of existing structures
within the health system, linked with reporting
and accountability structures.
2. Ensure health risk management is properly
reflected in sanitation legislation, regulations
and standards
• Review the public health eectiveness of existing
national and local legislation, regulations and
standards along the whole service and in all
settings (including in related sectors such as
agriculture and urban planning) to identify and
address impediments to improving sanitation.
• Explicitly recognize sewered and non-sewered
sanitation system types (including decentralized
systems), including the full service chains of both,
in relevant legislation and regulations at national,
sub-national, municipal and local levels.
• Regulate service quality for all steps in the
sanitation service chain, based on public health
risk assessment and management.
• Formulate sanitation technology performance criteria
and standards, including operation and maintenance
criteria and incremental standards if appropriate for
specic settings.
• Formulate standards for products made or
grown with sludge or wastewater that include
risk assessment and management approaches
to ensure appropriate controls in treatment,
production and use.
• Ensure legislation, regulations and standards
consider willingness and ability of users to pay, and
include tari structures and access to subsidies and
other nancial resources.
• Where regulatory enforcement is challenging or
unlikely due to capacity and other constraints, put
in place incentive-based approaches to encourage
compliance and improve the ability of poor
households to access safe sanitation technologies.
• Ensure that legislation and regulations allow for
and regulate participation of the private sector in
sanitation service provision.
• Protect sanitation workers and others who may
engage in emptying on-site systems from
occupational hazards through adequate health and
safety standards and standard operating procedures.
3. Sustain the engagement of the health sector
in sanitation through dedicated staffing and
resourcing, and through action on sanitation
within health services
• Review environmental health institutional
hierarchy and staffing needs at all levels, and
put in place a public sector service scheme,
training programmes, and mechanisms for sta
development and retention.
• Create senior posts with dedicated responsibility
for sanitation.
• Build capacity of environmental health sta to
fulfil health sector functions – contribution to
sanitation coordination, health in sanitation
policies, health protecting norms and standards,
health surveillance and response, sanitation in
health programme delivery, sanitation behaviour
change, sanitation in healthcare facilities.
• Establish sanitation oversight, monitoring and
enforcement mechanisms within the health
system, including routine monitoring of sanitation
in healthcare facilities.
• Gather and analyze relevant health and
epidemiological data to identify risks and high
priority areas for sanitation improvement and to
support setting of targets, priority intervention
areas and approaches and standards.
• Develop inspection and accreditation mechanisms
to manage sanitation-related risks in other sectors
(e.g. agriculture, environment, hospitality).
4. Undertake local level health-based risk
assessment to prioritize improvements and
manage system performance
• Dene sanitation at sub-national level as a basic
service for which local government is responsible
and accountable.
22
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 2
• Establish local government coordination groups
with senior representation from all relevant local
government departments and implementation
partners to align and coordinate sanitation
activities.
• Define health-protecting technologies in local
standards and guidelines and promote their use.
• Implement targeted and contextualized sanitation
promotion through dedicated sanitation
programmes addressing barriers to adoption
and use to create toilet demand as a necessary
precondition for toilet adoption and use.
• Design, implement manage and improve sanitation
systems for the entire sanitation service chain to
minimize health risks among users, workers and
communities using sanitation safety planning
principles.
• Allocate sucient nancial and human resources
for long-term implementation.
• Establish a robust sanitation monitoring
mechanism with public health oversight at the
lowest administrative level strengthening existing
structures and sta.
• Facilitate exchanges between local governments
to disseminate good practices and promote peer
competition on achievement of programme targets.
5. Enable marketing of sanitation services and
develop sanitation services and business
models
• Design the mix of sanitation services based on
an assessment of local level housing and sanitary
conditions, prioritizing institutionally and nancially
feasible interventions that address the greatest
identied public health risks in the shortest time.
• Establish a sustained marketing effort for safe
sanitation services to eliminate open defecation
and unimproved toilets.
• Promote private sector service provision for those
parts of the sanitation service chain with high
customer benet (e.g. toilet construction, and some
safe emptying services), considering public-private
partnership arrangements where appropriate.
• Use public funds to cover the affordability gap
between minimum sanitation service standards and
users’ ability and willingness to pay, with specic
measures to ensure that services also reach the
poorest and most vulnerable people.
• Invest in safe and eective solutions for emptying
on-site systems and treatment of faecal sludge
from on-site or o-site systems.
• Introduce nancial arrangements to facilitate large,
infrequent user costs such as sewer connection and
desludging fees, or facilities in rocky or ood prone
areas in line with policies, legislation, regulations
and standards that consider willingness and ability
to pay.
• Acknowledge the informal sanitation service
providers, recognizing that improved services will
have to compete and that their experience is a
valuable resource that should be utilized within the
formal system.
• Build sustainable service provider capacity to meet
national and local level targets and requirements
of legislation, regulations and standards.
• Enhance the market for sanitation services through
introduction of competition.
• Encourage innovation and experimentation
accompanied by rigorous monitoring and
evaluation of systems and proposed solutions.
23
CHAPTER 2. RECOMMENDATIONS AND GOOD PRACTICE ACTIONS
Chapter 2
Table 2.1 Evidence to recommendation table using the WHO-INTEGRATE framework (Rehfuess et al.)
Criteria Guiding
question
Rationale and evidence Judgement
Balance
of health
benets and
harms
Does the
balance
between
desirable and
undesirable
health eects
favour the
intervention
or “business
as usual”?
If the intervention is implemented as set out in these guidelines, undesirable eects are
very unlikely. Desirable eects include reduced exposure to faecal pathogens, reduced incidence
and prevalence of various infections and consequences of infection such as stunting, and
positive inuences on various dimensions of social and mental well-being such as privacy,
dignity, safety and reduction in shame, anxiety, fear, assault, and embarrassment.
If the intervention is not implemented, or not implemented as set out in these guidelines,
undesirable eects may happen at each step of the sanitation service chain, such as increased
exposure to excreta of users through open defecation or poor maintenance of toilet facilities;
of the wider community through poor containment and conveyance of faecal sludge; and of
workers through poor management practices. Inadequate shared and public toilets can also
result in harmful eects on broader well-being, such as shame and anxiety, exposure of certain
groups to other risks (for example, assault or harassment when using public or shared facilities),
or reinforcing stigmatization of specic groups by targeting them, thereby compounding the
likelihood of reversion to open defecation. Increased access to and use of toilets may still result
in adverse public health impacts if poor quality of the toilet or poor sanitation service chain
management results in discharge of untreated sludge into the environment in which people live
and work.
Favours
“business
as usual”
Probably
favours
“business as
usual”
Does not
favour
either the
intervention
or “business
as usual”
Probably
favours the
intervention
Favours the
intervention
Human
rights
and socio
cultural
acceptability
Is the
intervention
in accordance
with
universal
human rights
standards
and
principles?
The intervention, taking into account availability, accessibility, quality, aordability and
acceptability of safe sanitation services, is in accordance with the Human Right to Water and
Sanitation, which obliges all UN Member States to consider all aspects of universal access
to services. This includes increasing the number of people with access to at least minimum
services, improvement in levels of services, and explicitly targeting poor, marginalised and
disadvantaged people. It also contributes to the realization of the Human right to Health, and
the achievement of Universal Health Coverage.
Construction and management of sanitation services without due consideration of all human
rights criteria can result in exclusion of marginalized groups on the basis of physical, cultural
and gender discrimination.
No
Probably not
Uncertain
Probably yes
Yes
Is the
intervention
acceptable
to key
stakeholders?
If the intervention is implemented as set out in these guidelines, i.e. if it is designed and
delivered in a way that responds to cultural, social and economic context, as well as the needs
and preferences of individuals, households and communities, it is likely to be acceptable to
all key stakeholders. If the intervention is not implemented as set out in these guidelines,
acceptability of services may be reduced (e.g. inadequate privacy and safety of the toilet
and inadequate provision for menstrual hygiene management for women and girls, or use
of hardware or technologies such as pedestals and ushing options that do not meet user
preferences), resulting in lack of uptake of services, lack of use (including reversion to open
defecation), and lack of willingness to pay for higher quality services.
Compliance with sanitation standards may result in additional economic burden on poor
households, in terms of increased housing costs (including for construction of toilets, septic
tanks etc. where households own their home, as well as possibly higher renting costs). This
should be considered in intervention design and pricing structures for consumer services.
Landlords and informal sanitation service providers may resist regulation and enforcement due
to cost and inconvenience implications.
Punitive measures for sanitation enforcement may be intrusive if these result in substantive
inspection and penalties.
No
Probably not
Uncertain
Probably yes
Yes
24
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 2
Criteria Guiding
question
Rationale and evidence Judgement
Health equity,
equality
and non-
discrimination
What would
be the
impact of the
intervention
on health
equity,
equality
and non-
discrimination?
The intervention has the potential to address health inequalities at various levels,
including global (between countries), national (between geographic regions,
urban/rural populations and income groups) and local (in terms of gender, age,
social class and disability). The intervention, when applied at suciently large
scale (such as entire communities) and resulting in increased access to and use of
safe sanitation services, is particularly benecial for poor and vulnerable groups,
including women and children, who are more likely to be aected by excreta-related
infections and subsequent health outcomes, and less likely to be able to aord the
cost of treatment and other economic consequences of ill health and poor well-
being. If delivered appropriately, the intervention ensures access to services in a way
that enables improved social and economic inclusion.
Safe sanitation services may not be aordable to poor and marginalized groups,
and infrastructure may not be suciently accessible to all groups (such as children,
people with disabilities and older people). The impact of the intervention on health
equality and/or equity therefore depends on the way in which it is delivered, and
whether all forms of poverty and marginalization have been adequately considered.
Some forms of sanitation behaviour change interventions that encourage
incremental increases in access based on household investment may increase health
inequalities in the short-term. However, the availability of low-cost technologies, as
well as shared and public facilities, potentially reduces cost to a suciently low level
to allow aordability, while reducing the opportunity costs of not having access to
a toilet (in terms of time, illness and other well-being aspects that aect economic
productivity and poverty). Low-lying communities may be negatively aected by
untreated wastewater and facial sludge discharges if toilets are not coupled with a
safe service chain.
No alternative to the intervention exists, a key principle that underpins the Human
Right to Water and Sanitation.
Increased
Probably increased
Neither increased
nor decreased
Probably reduced
Reduced
Societal
implications
Does the
balance
between
desirable and
undesirable
societal
implications
favour the
intervention
or “business as
usual”?
If the intervention is implemented as intended, ensuring non-exclusion from
access to services, particularly of poor and marginalized individuals and groups, if
infrastructure is constructed in a sustainable manner, and if toilets are connected
to a safe sanitation system, undesirable societal or environmental implications are
unlikely. In addition to the positive societal impact in the reduction of infections,
the intervention potentially contributes to other social aspects such as poverty
reduction and increased earnings in the medium to long term, education (through
improvement of the schooling and teaching environment) and uptake of healthcare
services (through improvement in healthcare settings).
If not implemented as intended, undesirable implications may include discharge
of excreta to the environment in a way that exposes the wider community to
pathogens, and damages the ecosystems on which communities depend, e.g. in
terms of drinking water, recreation and livelihoods.
Favours “business
as usual”
Probably favours
“business as usual”
Does not favour
either the
intervention or
“business as usual”
Probably favours
the intervention
Favours the
intervention
25
CHAPTER 2. RECOMMENDATIONS AND GOOD PRACTICE ACTIONS
Chapter 2
Criteria Guiding
question
Rationale and evidence Judgement
Financial and
economic
considerations
What would
be the
impact of the
intervention
on nancial
and economic
considerations?
Large (national) scale implementation of the intervention is likely to require
signicant government, corporate and household investment in capital and
operational expenditure, including initial infrastructure construction and ongoing
operation and maintenance. Further public spending will be required to meet
the needs of sanitation and health systems, such as training, recruitment of
environmental health sta (technical and managerial), monitoring systems, and
development of behaviour change programmes. The impact on the economy
will depend on the resources used for such investments. Substantial loans to
government will result in interest implications, while substantial grants may have
inationary consequences.
These costs should be considered in comparison with the likely benets over the
medium to long term. Every USD spent on sanitation yields cost savings in terms of
reduced costs to the health system, increased available income for poor households
over the longer term and therefore more spending power, and increased workforce
productivity and eciency that ultimately contribute to economic growth.
Negative
Probably negative
Neither negative
nor positive
Probably positive
Positive
Feasibility and
health system
considerations
Is the
intervention
feasible to
implement?
The capacity to deliver universal safe toilet access and promote use varies
signicantly among and within countries. Eorts will be required to ensure a
sucient legal framework for sanitation, including coordination to address overlap
and inconsistencies. Eorts to address the relatively low inuence and resourcing of
environmental health within health ministries are likely to be required in order to
enhance health leadership and governance for sanitation.
In many low- and middle-income contexts, signicant investment will be required
to increase the capacity of health authorities and other government departments
to improve the demand for and supply of safe toilets. Delivery of sanitation
behaviour change interventions through health programmes may impact on the
workload of health workers (potential increase in terms of activities and supervisory
responsibilities, and potential decrease in terms of treatment of infections as well as
reliance on mass anthelminthic treatments).
Substantial investment may be required in improving sanitation infrastructure in
healthcare facilities at all levels of care, to enhance capacity for infection prevention
and control in healthcare settings, to improve uptake of health care services, and to
improve the working conditions of health care sta.
Despite these challenges, experience from several LMICs shows that this is feasible if
sanitation is politically prioritized and if resources are allocated rationally.
No
Probably not
Uncertain
Probably yes
Yes
26
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 2
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29
CHAPTER 3. SAFE SANITATION SYSTEMS
Chapter 3
3.1 Introduction
Safe sanitation systems separate human excreta from
human contact at all steps of the sanitation service
chain carrying excreta from the toilet to its eventual
safe use or disposal. Health hazards associated
with the sanitation chain may be microbial (the
focus of these guidelines), chemical or physical.
The denition of health is not merely the absence
of disease or inrmity but also a state of mental
and social well-being. Therefore, it is important to
acknowledge the importance of safe sanitation
systems in addressing psychosocial hazards that
impact on acceptability and use (i.e. aspects that
impact on well-being, such as toilet privacy) at the
toilet and containment steps.
A combination of technologies at each step of
the chain can be used and, when linked and
properly managed, can form a safe chain. The type
of technology needed is highly context specific
depending on local technical, economic and social
factors, and should be considered in the context
of the whole sanitation service chain, as well as a
citywide perspective. The impact of climate change
on the safety and sustainability of technologies and
technologies’ impacts on the national greenhouse
gas emissions prole should be taken into account.
This chapter identifies the key technical and
management features to ensure that users’ well-being
is improved and that all people’s risk as a result of
exposure to excreta is minimized for each step of
the sanitation service chain, from the toilet, through
containment – storage treatment on-site, conveyance,
treatment and end use/disposal. A glossary is provided
at the end of the document for technical terms.
The focus of these guidelines is on human excreta
emanating from all sources, including households,
commercial settings, institutions such as schools
and healthcare facilities, as well as workplaces and
public settings. The guidelines do not cover risks to
humans from hazardous substances within industrial
wastewater and sludges or their eect on wastewater
and sludge treatment processes.
Box 3.1 International Organization for Standardization (ISO) standards relevant for sanitation services
• ISO/FDIS 30500 (2018): Non-sewered sanitation systems – Prefabricated integrated treatment units – General safety and performance
requirements for design and testing
• ISO 24521 (2016): Activities relating to drinking water and wastewater services – Guidelines for the management of basic on-site domestic
wastewater service
• ISO 24510 (2007) Activities relating to drinking water and wastewater services – Guidelines for the assessment and for the improvement of
the service to users
• ISO 24511 (2007) Activities relating to drinking water and wastewater services – Guidelines for the management of wastewater utilities and
for the assessment of wastewater services
Chapter 3
SAFE SANITATION SYSTEMS
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WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 3
3.1.1 Hazard and exposure reduction
Box 3.2 Denitions (WHO, 2016)
Risk: The likelihood and consequences that something with a
negative impact will occur.
Hazard: A biological, chemical or physical constituent that can
cause harm to human health.
Hazardous event: any incident or situation that introduces or
releases the hazard (i.e. faecal pathogens) to the environment in
which people are living or working, or amplies the concentration
of the hazard in the environment in which people are living
or working, or fails to remove the hazard from the human
environment.
The risk of infection from exposure to faecal
contamination is a combination of the likelihood
of exposure to the hazard and the impact of the
pathogen hazard itself on the person exposed. The
hazard itself does not present a risk if there is no
exposure to it. This relationship is shown in Figure
3.1. Reducing the risk from faecal contamination is
therefore about reducing the faecal pathogen hazard
level (i.e. concentration or numbers of the pathogen)
and/or reducing exposure to the hazard of a potential
human host (Mills et al., 2018; Robb et al., 2017).
Increasing exposure
Low risk
High risk
Increasing hazard level
Increasing risk
Figure 3.1 Faecal contamination risk
To describe the principles of safe management it is
necessary to identify the various hazardous events
that could occur. Figure 3.2 shows an illustrative
excreta ow diagram highlighting that exposure to
Figure 3.2 Excreta ow diagram showing examples of hazardous events at each step of the sanitation
service chain (adapted from Peal et al., 2014)
Toilet
(Section 3.2)
O-site sanitation
On-site sanitation
Open defecation or
other direct discharge
e.g. dirty toilets,or
toilets with no
handwashing facilities
e.g. open defecation
e.g. septic tanks that are full &
overowing or connected to open
drains or water bodies
Exposure of humans to pathogens through unsafe sanitation management and/or unsafe discharges to the environment
e.g. dumping faecal sludge
directly into water bodies
e.g. treatment plant
overloaded or
dysfunctional
e.g. spillage of faecal sludge
during manual or motorized
emptying
e.g. sewers leak or overow
wastewater directly into
water bodies
e.g. end use
or disposal
not compatible with
level of treatment
Containment – storage/
treatment (Section 3.3)
Conveyance
(Section 3.4)
Treatment
(Section 3.5)
End use/disposal
(Section 3.6)
Safe
end use/
disposal
ush toilets
dry & pour
ush toilets
septic tanks, pits,
cartridges, containers
emptying &
transport
faecal sludge treatment
sewerage wastewater treatment
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CHAPTER 3. SAFE SANITATION SYSTEMS
Chapter 3
faecal pathogens in excreta can potentially occur
from hazardous events from every type of sanitation
system and at each point on the sanitation service
chain. The hazardous events caused by unsafe excreta
management can lead to exposure.
Hazardous events, control measures and exposure
groups
This chapter describes each step of the sanitation
service chain and the control measures that could be
used to reduce the risk of exposure.
Control measures are dened as any barrier or action
that can be used to prevent or eliminate a sanitation-
related hazardous event or reduce it to an acceptable
level of risk.
The people most likely to be exposed belong within
one of four risk groups:
• Sanitation system users: all people who use a toilet.
• Local community: people who live and/or work
nearby (i.e. people who are not necessarily users
of the sanitation system) and may be exposed.
• Wider community: the wider population (e.g.
farmers, lower lying communities) who are exposed
to (e.g. through recreation or flooding) or use
sanitation end use products (e.g. compost, faecal
sludge, wastewater) or consume products (e.g. sh,
crops) that are produced using sanitation end use
products intentionally or unintentionally, and may
be exposed.
• Sanitation workers: all people – formally employed
or informally engaged - responsible for maintaining,
cleaning or operating (e.g. emptying) a toilet or
equipment (e.g. pumps, vehicles) at any step of the
sanitation service chain.
3.1.2 Incremental control measures
In many countries, achieving safe sanitation systems will
require stepwise implementation. Incremental control
measures are highlighted for each step of the sanitation
service chain below that can be later upgraded to safe
sanitation when local technical, institutional, economic,
social and nancial capacity allows.
3.1.3 Sanitation system fact sheets
The sanitation system fact sheets in Annex 1 provide
guidance on some of the most frequently-used
sanitation systems. Each describes the applicability
of the system in dierent contexts; design, operation
and maintenance considerations; and mechanisms for
protecting public health at each step of the sanitation
service chain. Depending on the setting, various
sanitation technology and infrastructure options
can be designed, combined, operated and managed
at dierent scales to form a functional service chain.
Table 3.5 towards the end of this chapter provides a
summary of the systems included in the fact sheets
and their applicability in relation to physical and
enabling factors.
3.2 Toilets
3.2.1 Definition
The term ‘toilet’ here refers to the user interface with
the sanitation system, where excreta is captured,
and can incorporate any type of toilet seat or latrine
slab, pedestal, pan or urinal. There are several types
of toilet, for example pour- and cistern-ush toilets,
dry toilets and urine-diverting toilets.
The superstructure of the toilet may be a stand-
alone structure, or the toilet may be located within
a building (e.g. private house, a school, health care
facility, work place or other public setting).
3.2.2 Safe management at the toilet step
The key principle for safe toilet management is that the
design, construction, management and use is arranged
so that users are safely separated from excreta, avoiding
both active contact (e.g. from soiled surfaces) and
passive contact (e.g. via ies or other vectors).
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WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 3
Toilets should be maintained through cleaning (which
removes any faecal material and pathogens), so that the
risk for users is minimized. Those responsible for toilet
cleaning and maintenance should do so using methods
and equipment that protect them from the hazard.
The health of users extends beyond consideration
of exposure to pathogens in excreta; these include
issues related to accessibility, security, privacy and
menstrual hygiene management. Consideration of
these aspects is important to ensure the facility is
suitable for the intended users with suitable operation
and maintenance arrangements, so that they are less
likely to revert to unsafe sanitation practices (e.g.
open defecation). These aspects are discussed further
in Chapter 5 on sanitation behaviour change.
Reducing risk at the toilet and encouraging use
In order to reduce the (a) likelihood of exposure; (b)
the severity of any exposure to hazardous events; or (c)
both likelihood and severity, as well as to encourage use,
toilets must have a number of features (outlined below).
Design and construction
Toilets should be:
• Compatible with current and predicted future
water availability for ushing (if required), cleaning
and hand hygiene.
• Compatible with the subsequent containment,
conveyance and treatment technologies (on-site
or o-site) for safely managing excreta generated
through toilet use.
• Suitable, private and safe to use for all intended
users, taking into consideration their gender, age
and physical mobility (e.g. disabled, sick etc.).
The slab (or pedestal) should be designed and
constructed:
• From a durable material that can be cleaned easily
(e.g. concrete, breglass, porcelain, stainless steel,
durable plastic or smooth wood).
• So that the size and arrangement is appropriate
for all intended users (including e.g. children and
older people).
• So that stormwater is prevented from inltrating
the containment technology.
• For ush toilets – tted with a water seal or trap-
door to control odour and prevent rodents or
insects entering the containment technology.
• For dry toilets – tted with a removable, closely-
tted lid, to prevent rodents or insects entering
the containment technology and, if tted with a
ventilation pipe, a corrosion resistant y screen.
The superstructure should be designed and constructed
so that it prevents intrusion of rainwater, stormwater,
animals, rodents or insects. It should provide safety and
privacy with doors that are lockable from the inside for
public toilets, or toilets shared between households.
Culturally-appropriate anal cleansing materials should
be available within the toilet (i.e. water supply and
container for washing, or materials for wiping – with
a disposal container where required) and accessible
handwashing facilities with soap and water should
be available nearby in a location that encourages use.
Operation and maintenance
• Cleanliness: the toilet and all surfaces of the room
that it is in (e.g. bathroom, washroom, rest room,
cubicle etc.) should be kept clean and free of excreta.
• Cleaning arrangements: Locally-available cleaning
materials should be safely stored and used, and
all people carrying out cleaning should observe
safe working practices. Where the toilet is public
or shared, a regular cleaning schedule should be in
place, with provision made for supply of cleaning
materials and personal protective equipment (PPE).
• Where dry toilets are used, a ready supply of ash,
soil, lime or sawdust should be available within
the facility, with which users can cover faeces after
defecating. This helps to prevent ies and minimize
odours.
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CHAPTER 3. SAFE SANITATION SYSTEMS
Chapter 3
Additional features
In addition to design, construction, operation and
maintenance aspects there are several other features
that respond to human rights criteria (see Box 1.1) and
that aect toilet adoption and use and the likelihood
that users will keep the facility clean (and not revert
to open defecation). These include:
• Availability: There should be sucient facilities that
limit waiting to an acceptable length of time that
does not discourage use or cause inconvenience,
including in households, health facilities, schools,
work places and public places.
• Accessibility: The facility should be accessible at all
times for all intended users, taking into consideration
age, gender and disabilities of users. Where toilets are
sex separated, users should be able to access the
toilet matching their gender identity.
• Acceptability: The superstructure should provide
privacy and safety for the user, for example
through provision of light and a door lockable
from the inside; this is particularly important
where the toilet is shared or public or in a school,
health care facility or workplace. Facilities for
safe menstrual hygiene management should be
provided, such as a covered container for disposal
of menstrual hygiene products. Where the toilet
is shared or public, the container should be
sized according to the expected usage, with an
emptying and safe disposal arrangement and
schedule. Used menstrual hygiene products
should not be flushed down- or disposed into
the toilet.
Aspects related to quality are covered in the above
section on reducing the likelihood or severity of
hazardous events at the toilet and encouraging use.
In contrast, examples of toilets that do not reduce the
likelihood or severity of hazardous events include:
• Toilets that are not well constructed and/or made
of a non-durable material that prevents cleaning
of the slab (or pedestal).
• Toilets that are not kept clean and where excreta
remain on the toilet and/or surfaces of the room
housing the toilet.
• Toilets where no anal cleansing products, and/or
handwashing facilities and/or facilities for disposal
of menstrual hygiene products are available.
• Toilets that are kept locked for long periods of the
day or night, and/or do not oer sucient security
and/or privacy.
Toilets that do not meet safety, comfort and cleanliness
criteria may contribute to users resorting to open
urination and defecation.
Incremental control measures
This section highlights measures that can be
considered to overcome specic contextual issues such
as poverty, availability of resources and population
density. In remote rural areas, for example, where the
availability of materials is a limiting factor and/or the
cost of transporting a durable slab from a local town is
considered too high, households should at least cover
any wooden squatting slab with a coating of mortar.
This approach should allow the slab to be cleaned
more eectively and therefore limit exposure; however,
it will not be durable and may need replacing before
the pit has lled.
Shared or public toilets
Wherever possible, each household should use and
manage their own toilet, which is not shared with
another family or other users. However, there are
contexts where this is not practical, such as:
• in dense urban settlements where there may
be issues relating to land tenure and/or land
availability for the construction of individual
household toilets;
• in emergency situations where circumstances
dictate that the construction of individual toilets
is not feasible.
34
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 3
Where these situations are encountered, shared or public
toilets are a possible incremental control measure.
A single toilet shared between two or more households
or a public toilet can provide a satisfactory solution
provided each member of the households has equal
and ready access to the facility and that the toilet is
kept clean.
All shared or public toilets should have:
• a safe location and access route;
• doors that can be locked from the inside, and
lights;
• handwashing facilities with water supply and soap;
and
• menstrual hygiene management facilities;
• separate cubicles for men and women, or gender-
neutral cubicles that include handwashing and
menstrual hygiene management facilities
• suitable modications for all users e.g. an access
ramp and handrails for people with disabilities;
• A management system in place to operate and
maintain all the facilities provided.
Shared and public toilets may include shower and
laundry facilities. A well-run shared or public toilet
can provide a focal point or meeting place for the local
population, which can indirectly benet the users.
Management and maintenance of a public toilet is
potentially more challenging than management of
a shared, especially in popular or busy locations,
where the high use and diused responsibility means
that more frequent cleaning is required to maintain
each toilet. If users are charged fees, these should
be aordable for all to ensure that it does not limit
access to the facilities, which would potentially serve
to encourage open urination and defecation.
3.3 Containment – storage/treatment
3.3.1 Definition
The containment step is only relevant to non-sewered
sanitation systems and refers to the container,
usually located below ground level, to which the
toilet is connected. These include containers that are
designed for either:
• containment, storage and treatment of faecal
sludge and euent (e.g. septic tanks, dry- and
wet-pit latrines, composting toilets, dehydration
vaults, urine storage tanks etc.); or
• containment and storage (without treatment) of
faecal sludge and wastewater (e.g. fully lined tanks,
container-based sanitation).
3.3.2 Safe management at the containment –
storage/treatment step
The key principle related to this step is that the
products generated from the toilet are retained within
the containment technology and/or discharged to the
local environment in a manner that does not expose
anyone to the hazard.
Faecal sludge, for example, should be contained in an
impermeable technology (such as a septic tank) or in
a permeable technology such as a wet-pit that leach
directly into the subsoil. In either case sludge should
not enter the environment where it could directly
expose users and the local community to faecal
pathogens. Liquid effluent from an impermeable
container should discharge to a sewer or subsoil
structures via a soak pit or leach eld or should be
fully contained for later conveyance. It should not be
discharged to an open drain or water body where,
through contact or consumption, it could result
in exposure of the local community and/or wider
community to faecal pathogens.
35
CHAPTER 3. SAFE SANITATION SYSTEMS
Chapter 3
Bae
Euent outlet
to open drain or
water body
Inlet tee
Access covers
Inlet
Scum
Sludge
Settlement zone
Liquid level
Leakage from cracked / damaged septic tank
to groundwater
Septic tank overows
to local area
Pit or tank overows to local area
Euent outlet
to groundwater (via
soak pit or leacheld)
Groundwater level
Leakage from inlet
pipe to groundwater
Dry and wet pits
and open bottom tanks
Leachate from pit or tank to groundwater
Groundwater level
Septic tanks
Support ring
Figure 3.3 Hazardous events for permeable and impermeable containment – storage/treatment technologies*
* It should be noted that most of the hazards associated with a septic tank are also associated with non-engineered tanks of various types.
36
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 3
Where leachate from permeable technologies or
euent from impermeable technologies leaches into
subsoil structures, there is a risk that groundwater
and nearby surface water could be polluted,
potentially contaminating local water sources used
for drinking and domestic tasks (e.g. dish washing). If
groundwater is not used for domestic purposes and
other safe drinking-water sources are available, then
the risk from groundwater will be lower but may still
pose a risk if groundwater is occasionally used (e.g.
when the safe source is unavailable or unaordable).
Where groundwater is used for drinking, a risk
assessment should take the following factors into
account (Schmoll et al., 2006):
• the type of containment technology or technologies
in the area and degree of pathogen removal;
• hydraulic load from the container(s) on
groundwater;
• depth to groundwater table and soil/sub soil type;
• the horizontal and vertical distance from the drinking-
water source technology to the containment
technology or technologies in the areas; and
• the level of treatment (if any) applied to the
contaminated water before use.
As a general rule and without the risk assessment
outlined above, in order to reduce the risk from
contamination, the bottom of permeable containers
and soak pit or leach elds should be no less than
1.5m to 2.0 m above the water table at its highest
level during the year, permeable containers and leach
elds should be located down gradient, and at least
15 m horizontal distance from any drinking-water
source (Banks et al., 2002; Graham & Polizzotto, 2013;
Schmoll et al., 2006). If these distances cannot be
achieved due to population density or geographic
conditions, alternative designs (e.g. elevated pits)
should be considered. Figure 3.3 shows the possible
hazardous events for permeable and impermeable
containment technologies.
Reducing risk at the containment storage/treatment
step
Several design and construction, and operation and
maintenance aspects need to be considered to ensure
safe containment and on-site treatment.
Design and construction
The containment technology should be appropriate
for the local context, taking into consideration:
• the type and frequency of and accessibility for any
subsequent emptying (i.e. conveyance – Section 3.4);
• subsequent treatment technologies (if any)
(section 3.5);
• soil and sub-soil type;
• density of population and other containment
technologies;
• groundwater table and local drinking-water
sources used;
• potential for ooding;
• the toilet it is connected to; and
• number of users and type of input products
(e.g. faeces, urine, greywater and ushing water,
personal hygiene and anal cleaning products).
Where the toilet is connected to a:
• Septic tank: this should be functioning correctly,
sealed and impermeable, with two chambers and
the euent outlet discharging to a soak pit, leach
eld or piped sewer (solids-free sewers are sucient
when the connections are via septic tanks).
• Fully lined tank: this should have no euent outlet
and therefore frequent (and likely costly) emptying
or container exchange is needed (e.g. container-
based sanitation service models).
• Pit latrine or open-bottomed tank: this should be
functioning correctly through percolation to soil
sub-structures.
On-site treatment
Table 3.1 shows typical containment technologies and
their performance in terms of pathogen reduction
level (PRL). The table highlights that the products
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CHAPTER 3. SAFE SANITATION SYSTEMS
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from some systems, such as alternating twin pits
and compost toilets, can produce a stabilized sludge
which is safe to handle and use as a soil conditioner, if
operated properly (which can be hard to do in practice)
and provided that the contents remain dry. In contrast,
sludge emptied from a septic tank may have a high
pathogen level, depending on the amount of time it
has been stored, and requires further treatment before
use (section 3.5). Likewise, the euent from any septic
tank should either discharge to a soak pit (or leach
eld) where it can be adsorbed aerobically or conveyed
in a piped or solids-free sewer to a treatment plant.
Conveyance and o-site treatment of both sludges
and wastewater are explained in sections 3.4. and 3.5.
Operation and maintenance
• Where dehydration vaults or composting chambers
are used (i.e., dry twin pit toilets, urine diversion
toilets, container-based sanitation), a small amount
of ash, lime, dry soil or biomass waste (e.g. sawdust,
shredded bagasse, crushed peanut shells) should
be used to cover faeces after each use. This helps
to prevent ies, minimize odours and encourage
drying and decomposition.
• Any containment technology should be emptied
(or closed and sealed – see Section 3.6 on end use/
disposal) before there is a risk that the contents
ow into the local environment. As a guide, this
should be done when the distance from the
Toilet and containment
technology
Treatment objectives Pathogen
reduction
mechanism
Pathogen
Reduction Level*
Treatment products and pathogen
level**
Flush toilet with septic
tank connected to a soak
pit or leach eld
Biochemical oxygen
demand (BOD) reduction
(small) Stabilization
Storage
Adsorption (in soak
pit)
Low Liquid sludge with high pathogens.
Euent has high pathogens, but these
are adsorbed aerobically in the soak pit or
leach eld.
Flush toilet with single pit
or open-bottomed tank
Stabilization/nutrient
management
Adsorption Low Liquid sludge with high pathogens.
Liquid (leachate) high in pathogens is
adsorbed aerobically into soil. Pathogen
removal dependant on soil conditions.
Dry toilet with single pit
(abandoned when full)
Pathogen reduction
Stabilization/nutrient
management.
Storage
NB: single pits
should not be
emptied by hand
High Sludge stabilized into humus with low
pathogens.
Flush toilet with twin pits
for alternating use
Pathogen reduction
Stabilization/nutrient
management
Storage (At least 2
years)
Adsorption
High
(except Ascaris
eggs)
Sludge in pit ‘at rest’ stabilizes into a
humus with low pathogens.
Liquid (leachate) is adsorbed aerobically
into soil.
Dry toilet with twin pits
(fossa alterna)
Pathogen reduction
Stabilization
Storage
(at least 2 years)
High
(except Ascaris
eggs)
Sludge in pit ‘at rest’ stabilizes aerobically
into a humus with low pathogens.
Composting toilet Pathogen reduction
Stabilization/nutrient
management
Temperature
Storage
Sludge – Med
Leachate – Low
Dewatered stabilized sludge (compost)
with medium amount of pathogens.
Leachate with high pathogens.
Sources: Adapted from WHO (2006); Tilley et al. (2014); Strande et al. (2014).
* PRL Pathogen reduction level (log
10
reduction) for well-designed, well-functioning systems: L - Low = <1 log
10
; M - Medium = 1 to 2 log
10
; H - High = >2 log
10
. PRL for bacteria used by
way of illustration, and may not apply to viruses, protozoa and helminths
** Pathogen level (pathogens per litre): Low = <2 log
10
; Medium = 2 to 4 log
10
; High = >4 log
10
Table 3.1 Treatment performance of containment technologies
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WHO GUIDELINES ON SANITATION AND HEALTH
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underside of the top of the container to the surface
of the faecal sludge (or supernatant) is around 0.5
metres (Franceys, Pickford & Reed, 1992; ARGOSS,
2001). Sludge accumulation rates vary widely
by setting, habits and technology (Strande et al,
2014).
• Twin pit toilets should be carefully managed,
ensuring that only one pit is used consistently
until it is full, and then sealed o and stored for at
least two years, while using the other pit.
• When full, some containment technologies are
not emptied at the household level but the whole
container has to be removed from the premises
and transported away. In exchange for the full
container, the household receives a clean, empty
container. This approach is known as container-
based sanitation.
• Full consideration of how emptying and transport
operations should be managed for all containment
technologies is discussed in the next step –
conveyance.
• Euent discharge pipes (if any) should be kept
clear of blockages.
In contrast, examples of containment technologies
that do not reduce the likelihood or severity of
exposure to hazardous events include:
• Any containment technology (septic tank, fully
lined tank, pit latrine, open-bottomed tank etc.)
that has an euent outlet discharging to an open
drain, a water body or to open ground.
• Any containment technology that is poorly
designed or constructed and where there is a
high likelihood that the leachate is contaminating
groundwater, local drinking-water sources or
drinking-water within underground pipes.
• Where bucket latrines are provided. This
containment technology does not separate the
user or workers from excreta.
• Where hanging toilets are provided, for instance
where a toilet is provided but there is no
containment technology or connection to a sewer,
and instead the toilet discharges direct to a water
body or the ground. This arrangement poses a risk
to the local community and wider community.
• Operation and maintenance procedures that result
in:
– Operation inconsistent with the technology
design (e.g. twin pits used in tandem rather than
alternating)
– any euent discharge pipe becoming blocked,
causing the faecal sludge and/or effluent to
overow into the toilet and/or into water bodies
or on to open ground; or
– any containment technology that is either
physically not emptiable, not emptied when
full (for technologies that require periodic
emptying) or not closed and sealed, causing
the faecal sludge and/or euent to overow
into the toilet and/or into water bodies or onto
open ground.
Incremental control measures
There are no incremental control measures for
containment.
In some locations, where containment technologies
discharge to open drains, the drains are covered
or partially covered with concrete or stone slabs.
However, this is not considered to be a suitable
incremental control measure. The impermeable
covering reduces some of the risks from faecal
pathogens in the euent for the local community.
However, open roadside-drainage is provided for
stormwater management, and covering the drain will
not facilitate cleaning which, if they become blocked,
can cause ooding during periods of heavy rainfall
– leading to increased exposure to wastewater (and
therefore pathogens) for the local community and
wider community. The practice is impractical and/or
costly where the drain dimensions are large.
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CHAPTER 3. SAFE SANITATION SYSTEMS
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3.4 Conveyance
3.4.1 Definition
Conveyance refers to the deliberate movement of
wastewater or faecal sludge from a containment
technology to o-site treatment, and/or end use/
disposal. Conveyance systems can be sewer-based
or based on manual or motorized emptying and
transport.
Sewer-based systems
Sewer-based systems comprise networks of
underground pipes. Types of sewerage include (Tilley
et al., 2014):
• conventional gravity sewers: convey blackwater
from toilets and greywater along with, in many
cases, industrial euents and stormwater through
large diameter pipes to a treatment facility, using
gravity (and pumps when necessary)
• simplied sewers: a lower cost design installed
using smaller pipes at a lower depth and shallower
gradient than conventional gravity sewers.
• solids-free sewers: similar design to simplified
sewers but including pre-treatment of sludge to
remove solids.
Simplied and solids-free sewers can be implemented
as condominial sewerage schemes that incorporate
user and authority networking and consultation.
Manual and motorized emptying and transport
systems
Manual and motorized emptying and transport refers
to the dierent ways by which faecal sludge can be
removed from the facility location.
Manual emptying of pits, vaults and tanks can be
done in one of two ways:
• using buckets and shovels; or
• using a portable, manually operated sludge pump
(while this may be mechanized, it still requires
manual/physical handling)
Both manual and motorized emptying may carry
risk of possible contact with the faecal material and
in some cases motorized emptying needs to be
combined with manual emptying to remove the
densest material. Some containment technologies
can only be emptied manually (e.g. fossa alterna or
dehydration vaults). These technologies are emptied
most commonly with a shovel because the material
is solid and cannot be removed with a vacuum or
a pump. The emptied faecal sludge is collected in
barrels or bags or put into a cart and transported
away from the site.
Motorized emptying and transport (also known
as mechanical emptying and transport) refers to
the use of any vehicle or device equipped with a
motorized pump and a storage tank for emptying
and transporting faecal sludge. People are required
to operate the pump and manoeuvre the hose, but
the faecal sludge is not manually lifted or transported.
Wet systems such as septic tanks and fully lined tanks
are commonly emptied using motorized emptying
and transport.
Containers used with container-based sanitation
are not emptied at the household level; instead,
the sealed container and its contents are manually
removed from the premises and should be conveyed
to a treatment facility. Unlike bucket toilets, sealed
containers removed from the premises prevent
contact by users and workers with fresh faeces.
3.4.2 Safe conveyance
The key principle for safe conveyance is limiting
exposure of the workers carrying out operation and
maintenance, the community living and working
in the vicinity of the work, and wider community
who could each be exposed to pathogens through
ingestion and inhalation of faecal pathogens while
at home or work, in recreational and drinking-water
supply and food supply chains.
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WHO GUIDELINES ON SANITATION AND HEALTH
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Sewers
If well designed, constructed, operated and maintained,
sewers are an efficient means of transporting
wastewater, requiring comparatively little maintenance.
However, all sewer pipes can become clogged with
solid waste and other solids, which require removing
by rodding, ushing, jetting or bailing. Where used,
pumps, interceptor tanks and access chambers require
maintenance. Carrying out sewer maintenance may
expose workers to hazardous wastewater and/or toxic
gases. Leakage from sewers poses a risk of wastewater
exltration and groundwater inltration. Exltration to
groundwater and water supplies could expose the local
community and wider community to faecal pathogens
via ingestion. Where there is concern that groundwater
or piped water quality is being compromised, risk
assessment should be based on (Schmoll et al., 2006):
• the frequency of sewer breaks;
• age and method of construction of the sewer;
• depth of the sewer relative to water supply pipes;
• grading of material surrounding the pipe; and
• groundwater level.
Active monitoring programmes (e.g. the use of sewer
inspection cameras) may assist in identifying the
extent and nature of contamination from sewers.
Manual and motorized emptying and transport
Both manual and motorized technologies require
workers (service providers, emptiers, desludgers
and exhausters) to handle tools and equipment that
have contact with faecal sludges (including the liquid
supernatant or euent if any) Workers entering pits
should be avoided due to the risk of injury or death from
pits collapsing or inhalation of toxic gases. Emptying
may put the users and community at unacceptable
risks resulting from exposure to spillage as the work
proceeds. The key principle for safe emptying and
transport is therefore limiting the exposure of these
groups to the hazardous faecal sludge.
The level of risk depends on the type and quantity of
faecal sludge being emptied. For instance, fresh faecal
sludge emptied from a septic tank connected to a
busy public toilet is more hazardous to human health
than the faecal sludge that has been accumulating
slowly in a household’s dry pit latrine for two years or
more because there will have been some pathogen
die o in the older accumulated sludge.
From a public health perspective, manual emptying
carries a greater risk than motorized emptying, as there
is greater likelihood of workers having contact with
the faecal sludge. Manual emptying is stigmatized,
low status work affecting the personal and social
well-being of sanitation workers. Therefore, wherever
possible motorized emptying and transport should
be prioritized over manual emptying and transport.
Reducing risk at the conveyance step
Design and construction of the conveyance system
should be:
• compatible with the containment technology;
• compatible with the characteristics of the contents
to be emptied;
• compatible with the following treatment and end
use/disposal technologies; and
• appropriate for the local context taking into
consideration the hazardous events identied in
Figure 3.4 and, in particular, minimizing the need
for manual handling of faecal sludge by sanitation
workers.
Operation and maintenance considerations include:
• All workers should be trained on the risks of
working with sanitation systems, including
handling wastewater and/or faecal sludge, and be
equipped to follow standard operating procedures.
• All workers should consistently and correctly
wear PPE – gloves, masks, hats, full overalls and
enclosed waterproof footwear – particularly where
manual sewer inspection and cleaning or manual
emptying is required.
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CHAPTER 3. SAFE SANITATION SYSTEMS
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GROUND LEVEL
CUT AWAY VIEW:
BELOW GROUND LEVEL
Manual emptying
and transport
Worker contact
during emptying
Mechanical emptying
and transport
Support ring
Worker contact and spillage during
manual handling from bucket to transport
and/or during transport
Spillage during emptying
or transport from equipment
malfunction
Discharge without treatment
to open drains, water bodies
or open ground
Discharge without treatment
to open drains, water bodies
or open ground
Leakage from cracked/damaged
sewer pipes or joints
to groundwater
Water body
Groundwater level
Worker contact during sewer
cleaning and other
maintenance
Overow of sewers due to
blockage, failure, or
during high ows
Figure 3.4 Hazardous events for conveyance technologies
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WHO GUIDELINES ON SANITATION AND HEALTH
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• To avoid asphyxiation, adequate ventilation
should occur before entering any confined
space (containment or sewers), using ventilation
equipment when necessary. Entering conrmed
space should never be done alone.
• Workers should avoid entering the pit either by
using equipment that avoids the need to enter or
by only partially emptying the pit.
• Only dedicated tools and equipment should be
used, which are t for purpose (e.g. long handled
shovels and long suction hoses) and cleaned
with water between uses. Wash water should be
directed into the containment technology.
• All workers should wash thoroughly with soap
immediately after coming into contact with
hazardous wastewater and/or faecal sludge.
• All clothing (both PPE and under layers) should be
laundered daily and all rubber boots and gloves
should be cleaned with water. Wash water should
be directed into the containment technology.
• Spillage should be minimized, and spills should
be contained and cleaned up when they do occur.
For example, having completed the emptying of
a containment technology any aected property
in the immediate vicinity of the event, should be
washed down/cleaned with water.
• All workers should be provided with regular health
checks, receive medical advice and treatment (e.g.
deworming), and be adequately vaccinated against
potentially relevant infections (such as tetanus,
polio, typhoid fever, hepatitis A and B (CDC, 2015),
depending on the epidemiological context).
Examples of conveyance methods that do not reduce
the likelihood or severity of exposure include:
• Any untreated wastewater in sewerage, which
is not delivered to treatment plants but is
released to open drains, water bodies or to the
ground. Examples include sewer blockages or
pump failures that cause wastewater overows
into surface waters and sewer defects that cause
inltration to overload the system, or exltration
to contaminate groundwater and/or local water
supply pipelines.
• Any untreated faecal sludge transported manually
or mechanically, which is not delivered to treatment
plants but discharged elsewhere. For instance,
where untreated faecal sludge is discharged into
open drains, nearby streams or rivers, or where it is
used as a soil conditioner.
• Use of ooding out (or gravitational emptying) of
pits. This is where pits are emptied by washing the
contents out through a pipe inserted into the pit.
The pipe is connected to a lower lying drain, water
body or hole dug to receive the faecal sludge.
• Any manual or motorized transport carrying faecal
sludge which, while being driven or operated,
causes the faecal sludge to leak or spill onto other
road users. For instance, faecal sludge from septic
tanks carried in a tractor-pulled trailer that leaks
out of the trailer onto the road.
Incremental control measures
Minimizing risks from manual emptying
While motorized emptying and transport is preferred for
conveying faecal sludge from containment technologies,
there are context specic reasons why manual emptying
is used in some settings. These include:
• Availability of motorized emptying services: In
many locations, despite high demand, few public
or private motorized emptying service providers
are present.
• Access to the containment technologies: Large
vacuum trucks are unsuitable for emptying
containers in dense, urban settlements that are
hard to access. Often these facilities can only be
emptied using a combination of portable pumps,
shovels and manual transport.
• Informality: In most locations manual emptying
remains an informal and low-cost service. Informal
services are perpetuated though lack of regulation
of service quality or worker protection, and
customer demand for comparatively low-cost
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CHAPTER 3. SAFE SANITATION SYSTEMS
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services. However, informal services are not always
satisfactory for the household, or from a public
health perspective.
• Pumpability: Relatively fresh, wet sludge can be
pumped with a vacuum truck, while drier, typically
older faecal sludge usually requires removal with
a shovel. The presence of solid waste in containers
also reduces pumpability.
• Availability and accessibility of treatment plants:
Where treatment plants are available and are
designed to receive faecal sludge, the sites are
often located remotely from populations, with
attendant costs that lead to high fees. Households
may resort to manual emptying that is not always
done safely. In this circumstance households
should either bury and cover faecal sludge nearby
or construct a new latrine.
• Acceptability: In contexts where discussion of excreta
or how to manage it is taboo, emptying at night when
the activities are perceived to be hidden from view
is often favoured and manual rather than motorized
emptying is a discrete option in these circumstances.
Working in the dark can be dicult and dangerous.
Where these conditions prevail, manual emptying
of containment technologies may be the only viable
solution. Nevertheless, manual emptying should be
minimized; for instance, motorized and/or manual
pumps should be used to remove as much of the
contents as possible before using shovels and buckets
to empty the remainder. Where manual emptying is
used, the exposure control measures in the section
on reducing the risk of exposure at the conveyance
step should be followed. However, where manual
emptying is informal, these measures may be hard
to implement.
Transfer stations and sewer discharge stations
Transfer stations and sewer discharge stations act
as intermediate dumping points for faecal sludge
when it cannot be easily transported to a remote
treatment facility. A vacuum truck empties transfer
stations when they are full and transports the faecal
sludge to a treatment plant. Sewer discharge stations
are connected to a conventional gravity sewer main.
Faecal sludge emptied into the discharge station is
released into an adjoining sewer main either directly
or preferably at timed intervals (e.g. by pumping) to
optimize the performance of the sewer and of the
treatment plant and/or reduce peak loads.
Transfer stations and sewer discharge stations are a
good choice for use in urban areas where treatment
plants for faecal sludge distant. Establishing multiple
stations may reduce transport costs and help to
reduce faecal sludge dumping, especially where
manual emptying and transport is common, and
the treatment plant is remote. Siting and land
requirement for transfer stations may also be less
onerous than for treatment plants.
Sewer discharge stations need to be properly
designed and/or operated, especially if retro-tted to
an existing wastewater system. If thick faecal sludge is
discharged into a sewer that is not designed to receive
such sludge, it may cause a blockage and result in the
sewer overowing or, if the associated treatment
works is not designed to receive concentrated faecal
sludge, it may cause a failure of the treatment process.
Both problems can be expensive to rectify.
Combined sewer overflows
A combined sewer system collects any combination
of rainwater, stormwater, domestic wastewater and
industrial wastewater into one sewer. Under normal
(dry) weather conditions, the combined system
transports all collected wastewater to a wastewater
treatment plant, before discharge for end use/disposal.
However, under high (peak) flow conditions, for
instance as a result of heavy rainfall or snow melt,
the volume of wastewater can exceed the capacity
of the treatment plant. When this occurs, untreated
stormwater and wastewater discharge without
treatment to nearby streams, rivers and other water
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WHO GUIDELINES ON SANITATION AND HEALTH
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bodies. These events are referred to as combined sewer
overows (CSOs) and, if the contents of the combined
sewer include untreated domestic wastewater, can
result in high pathogen loads in the receiving waters
(US EPA, 2004), with a corresponding high risk to wider
community. Increased intensity of rainfall associated
with climate change is likely to increase the frequency
and volume of CSOs.
Due to the high risk as a result of exposure to pathogens
caused by CSOs, combined sewers are not considered
to provide safe sanitation. However, in many locations
worldwide, combined sewers continue to operate.
In these situations, it is advised that any combined
sewer system be considered as an incremental control
measure and should be combined with other measures
to prevent exposure (e.g. public awareness or overows
and temporary closure of contaminated bathing site)
during CSO events. In preference, context specific
schemes for retention and infiltration or discharge
of stormwater and/or a separate drainage system for
stormwater should be provided.
3.5 Treatment
3.5.1 Definition
Treatment refers to the process(es) that changes the
physical, chemical and biological characteristics or
composition of faecal sludge or wastewater so that
it is of a quality that is t for purpose for the intended
next use or disposal (Blockley, 2005; Strande et al.,
2014) taking into account additional barriers in place
at the end use/disposal step.
Treatment can be sub-divided into three groups:
• those comprising technologies for containment
and storage/treatment of wastewater and faecal
sludge on-site (Section 3.3);
• those comprising technologies for the treatment of
wastewater (containing one or more of blackwater,
brownwater, greywater or euent) treated o-site;
and
• those comprising technologies for the treatment
of sludge o-site.
3.5.2 Safe treatment
To safeguard public health, it is imperative to design
and operate the facility for a specic end use/disposal
objective. This is the key principle at the treatment
step. For instance, where euents are to be used
for irrigation or discharged into water bodies used
for drinking or recreation, or where sludge is to be
used as a soil conditioner for crop production, the
treatment process should be designed on the basis of
pathogen removal, reduction or inactivation. With the
hazard eliminated or reduced to an acceptable level,
the risk to wider community exposed to the hazard
is also reduced. The risk level is dependent on the
likely exposure of humans (i.e. use by consumers) to
the pathogens in the euent or sludges.
In general, a treatment plant with a good pathogen
removal performance will also have a good physical
and chemical removal performance but the converse
is not necessarily true (Cairncross & Feachem, 2018).
A focus on the pathogen removal (reduction or
inactivation) is therefore advised during treatment
process design. However, as well as an understanding
of the required treatment eectiveness and euent
or sludge usage downstream, there are many issues
to consider in selection of a treatment process (for
further guidance see Strande et al., 2014; Metcalfe &
Eddy, 2014), including:
• the predicted inow and characteristics of the
inuent or faecal sludge;
• available land;
• available energy sources;
• available human resource capacity;
• location of population centres;
• topography;
• soil characteristics;
• water table;
• local climate and prevailing winds;
• seasonal and climatic variations;
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CHAPTER 3. SAFE SANITATION SYSTEMS
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• overall capital cost; and
• likely operation and maintenance costs.
Workers’ health is also important, as people operating
and maintaining treatment technologies are at risk
from exposure to hazardous wastewater and faecal
sludge. The people they regularly interact will (e.g.
their families and co-workers) may also be indirectly
at increased risk. Therefore, all workers should be
trained in the correct use of all tools and equipment
they operate, wear PPE and follow SOPs. The level of
exposure is inuenced by the design and construction
of the treatment technologies and, where more
than one technology is used, their conguration. For
instance, to avoid manual handling, faecal sludge
and wastewater ow should minimise the production
of aerosols ow by gravity, be pumped, or moved
mechanically between technologies.
Liquid effluent and sludges from treatment
The output from wastewater treatment and from
faecal sludge treatment processes consists of both
liquid euent and solid sludge. The characteristics
of each of these fractions will vary, depending on the
source, process used and other factors. However, a key
principle for safe management is that, regardless of the
source (e.g. wastewater from sewer-based technologies
or faecal sludge from on-site sanitation), both fractions
may require further treatment before end use/disposal.
For example, when wastewater is treated in a waste
stabilization pond the sludge that settles in the bottom
of the anaerobic and facultative ponds requires not
only periodic removal but, depending on the intended
end use/disposal, it may also require further treatment.
Similarly, where faecal sludge treatment generates
a liquid euent, for instance from unplanted drying
beds, it typically requires further treatment before its
intended end use/disposal.
Established treatment technologies
Table 3.2 shows the established o-site technologies
commonly used for treatment of wastewater, which
can also be applied to treat the liquid effluent
produced from faecal sludge treatment. Table 3.3
shows the established technologies commonly
used for treatment of faecal sludge and these can
be applied to treat the wastewater sludge produced
from wastewater treatment.
For each technology, the treatment objectives,
pathogen reduction mechanisms, likely pathogen
reduction level (PRL) and output treatment products
are given. The tables highlight the wide range of
treatment objectives (from suspended solid reduction
and dewatering to nutrient management and
pathogen inactivation) and the treatment products
produced. For each treatment product produced, an
estimate of the likely pathogen level is also given.
The listed processes can be applied at different
scales, from large centralised plants for an urban
area to smaller decentralised units serving a
district, neighbourhood or institution, although
the characteristics of each technology inuences its
suitability for these dierent settings.
Wastewater treatment processes
The established wastewater treatment technologies
in Table 3.2 are grouped under two categories: high
ow rate technologies, and low ow rate technologies,
which are all biological processes. The high ow rate
processes are mostly engineered structures with short
retention times. The technologies are listed as either
primary, secondary or tertiary treatment technologies.
Typically, the processes are combined in series, with
a primary treatment step to settle solids followed by
a secondary treatment step to biodegrade organic
substances and may include tertiary technologies for
the removal of specic contaminants (e.g. nutrient
removal, ltration, ultraltration or disinfection for
removal of pathogens). When tertiary treatment
technologies are used, the overall wastewater
treatment process is generally described as “advanced
wastewater treatment.”
46
WHO GUIDELINES ON SANITATION AND HEALTH
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Treatment process Level Treatment objectives Pathogen reduction measures PRL* Treatment products &
pathogen level**
Low ow rate
Waste stabilization
ponds
NA BOD reduction
Nutrient management
Pathogen reduction
Aerobic ponds (maturation)
Ultraviolet radiation
H Liquid sludge with low
pathogens
Euent with low pathogens
Constructed wetlands Secondary
or Tertiary
BOD reduction
Suspended solid removal
Nutrient management
Pathogen reduction
Natural decay
Predation from higher organisms
Sedimentation
UV radiation
M Plants – no pathogens
Euent with medium pathogens
High ow rate
Primary sedimentation Primary Suspended solid reduction Storage L Liquid sludge with high
pathogens
Euent with high pathogens
Advanced or
chemically enhanced
sedimentation
Primary Suspended solid reduction Coagulation/occulation
Storage
M Liquid sludge with medium
pathogens
Euent with medium pathogens
Anaerobic upow
sludge blanket reactors
Primary BOD reduction Storage L Liquid sludge with high pathogens
Euent with high pathogens
Biogas
Anaerobic baed
reactors
Primary/
Secondary
BOD reduction
Stabilization/nutrient
management
Storage L Liquid sludge with high pathogens
Euent with high pathogens
Biogas
Activated sludge Secondary
BOD reduction
Nutrient management
Storage M Liquid sludge with medium
pathogens
Euent with medium pathogens
Trickling lters Secondary Nutrient management Storage M Liquid sludge with medium
pathogens
Euent with pathogens
Aerated lagoon and
settling pond
Secondary BOD reduction
Pathogen reduction
Aeration M Liquid sludge with medium
pathogens
Euent with pathogens
High rate granular or
slow rate sand ltration
Tertiary Pathogen reduction Filtration H Euent with low pathogens
Dual media ltration Tertiary Pathogen reduction Filtration H Euent with low pathogens
Membranes Tertiary Pathogen reduction Ultraltration H Euent with low pathogens
Disinfection Tertiary Pathogen reduction Chlorination (oxidation) H Euent with low pathogens
Disinfection Tertiary Pathogen reduction Ozonation H Euent with low pathogens
Disinfection Tertiary Pathogen reduction Ultraviolet radiation H Euent with low pathogens
Table 3.2 Established wastewater treatment technologies
Sources: Adapted from WHO (2006) (Vol. 2, p.81); Tilley et al. (2014); Strande et al. (2014).
* PRL Pathogen reduction level (log
10
reduction) for well-designed, well-functioning systems: L - Low = <1 log
10
; M - Medium = 1 to 2 log
10
; H - High = >2 log
10
. PRL for bacteria used by
way of illustration, and may not apply to viruses, protozoa and helminths
** Pathogen level (pathogens per litre): Low = <2 log
10
; Medium = 2 to 4 log
10
; High = >4 log
10
47
CHAPTER 3. SAFE SANITATION SYSTEMS
Chapter 3
The low flow rate biological processes are mostly
pond-based systems with long retention times. They
are most commonly the lowest-cost treatment option
in warm climate locations, where inexpensive land is
available and where the energy/electricity supplies
may be unreliable or prohibitively expensive. Waste
stabilization ponds generally comprise three ponds
connected in series that provide a full treatment process
of sedimentation, biodegradation and pathogen
removal. Constructed wetland technologies, however,
provide either secondary or tertiary treatment only
and are generally preceded by a sedimentation and/
or biological treatment process.
How these wastewater treatment processes work and
their respective pathogen reduction mechanisms and
specic operation and maintenance requirements
is complex; details can be found in various sources
including WHO (2006); Metcalf and Eddy (2014);
Cairncross and Feachem (2018).
Sludge treatment processes
The established sludge treatment processes shown
in Table 3.3 are grouped according to their treatment
objective, namely dewatering, stabilization, nutrient
management and pathogen reduction. A full
explanation of these sludge treatment processes is
available in Strande et al., 2014, Strande, 2017 and
Tayler, 2018.
When designing a faecal sludge or a wastewater
treatment process, the choice of technologies, and
their sequence, must be determined with a full
understanding of the output products and their
eventual end use or disposal. For instance, if the end
use product of faecal sludge is a cement additive,
then the sludge requires dewatering and drying but,
since the cement manufacturing process destroys
all pathogens, pathogen inactivation at the faecal
sludge treatment plant is not required. In contrast, if
a soil conditioner (such as compost) is the required
Treatment
technology
Treatment
objectives
Pathogen reduction
measures
PRL* Treatment products & pathogen level**
Settling-thickening
ponds and tanks
Dewatering Storage Low Liquid sludge with high pathogens
Euent with high pathogens
Unplanted drying
beds
Dewatering Dehydration
Ultraviolet radiation
Storage
Low Dewatered or dry sludge with high
pathogens
Euent with high pathogens
Planted drying bed Dewatering
Stabilization/nutrient
management
Dehydration
Ultraviolet radiation
Storage
Sludge – High
Euent – Low
Plants – no pathogens
Dry stabilized sludge with low pathogens
Euent with high pathogens
Co-composting Pathogen reduction
Stabilization/nutrient
management
Temperature
Storage
Sludge – High Dewatered stabilized sludge (compost) with
low pathogens
Burial Stabilization/nutrient
management
Pathogen reduction
Storage
Adsorption
High Trees or plants – no pathogens
(and buried, stabilized sludge with low
pathogens)
Sources: Adapted from WHO (2006) (Vol. 2, p.81); Tilley et al. (2014); Strande et al. (2014).
* PRL Pathogen reduction level (log
10
reduction) for well-designed, well-functioning systems: L - Low = <1 log
10
; M - Medium = 1 to 2 log
10
; H - High = >2 log
10
. PRL for bacteria used by
way of illustration, and may not apply to viruses, protozoa and helminths
** Pathogen level (pathogens per litre): Low = <2 log
10
; Medium = 2 to 4 log
10
; High = >4 log
10
Table 3.3 Established sludge treatment processes
48
WHO GUIDELINES ON SANITATION AND HEALTH
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end product, the faecal sludge requires a process
that ensures pathogen inactivation (e.g. dewatering
and drying prior to co-composting with organic solid
wastes). When properly designed and operated, the
co-composting process inactivates the pathogens
making waste safe for farmers, food product handlers
and consumers to handle (Coe et al., 2016).
Treatment processes need to be properly operated
and maintained (following SOPs) and combine
multiple barriers WHO, 2006; WHO, 2016) to ensure
safety of the end product.
Transferring and emerging faecal sludge
treatment processes
Some wastewater treatment processes are also
applicable for faecal sludge treatment; these are
known as ‘transferring’ treatment technologies and
include mechanical dewatering, alkaline treatment,
incineration, anaerobic digestion, pelletizing and
thermal drying. These are not widely used but
research is ongoing to establish their relevance and
eectiveness. Research is also being conducted on
emerging faecal sludge treatment technologies. These
include nutrient recovery through vermicomposting
and opportunities for resource recovery in addition
to soil conditioning and water reclamation (e.g.
energy reclamation products such as liquid fuel from
biogas, biodiesel and synthetic natural gas treatment
technologies; and protein for animal feed by feeding
black soldier y larvae on faecal sludge).
These processes are addressed separately because,
when compared with the established technologies,
the level of expertise required to design and operate
them is much higher. However, as further research is
carried out, which leads to further renement and
improvement of the processes, it is likely that many of
the transferring and emerging processes will become
established (Strande et al., 2014; Strande, 2017).
Reducing risk at the treatment step
In order to reduce the likelihood or severity of
hazardous events, treatment technologies should
have the following design, construction, operation
and maintenance features.
Design and construction
• Based on the local context taking into consideration
the characteristics of the inuent, local climate and
seasonal variations and the available energy sources
and human resource capacity.
• Compatible with the following end use/disposal
type (Section 3.6).
Operation and maintenance
• Treatment plant management should follow
risk assessment and management processes to
identify, manage and monitor risks throughout the
system to meet treatment objectives.
• All workers operating and maintaining treatment
technologies should follow standard operating
procedures (SOPs) and wear personal protective
equipment (PPE).
In contrast, treatment technologies that do not
suciently reduce the risks include any treatment
technology where the level of pathogen removal
and end use/disposal type does not safeguard
downstream consumers. For instance, where:
• A treatment technology is overloaded so that
it works sub-optimally or fails completely. For
example, where fresh faecal sludge is discharged
to a waste stabilization pond designed for
wastewater treatment only, causing failure of the
treatment technology resulting in no or very low
pathogen removal.
• A treatment technology is dysfunctional. This could
be a short-term problem where energy required
to operate equipment is not available or, longer-
term, when the expertise of workers is insucient
to operate or repair equipment.
49
CHAPTER 3. SAFE SANITATION SYSTEMS
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As these three situations remain very common, also
in locations where emerging safe sanitation systems
are present, water bodies have to be used with care
for any recreational purposes or productive reuse
(Drechsel et al., 2010; WHO, 2003).
Incremental control measures
Treating faecal sludge with influent wastewater
(co-treatment) is relatively common in low-income
settings where faecal sludge management is not well
developed and there are no dedicated faecal sludge
treatment facilities. In such locations, vacuum truck
operators are permitted to discharge faecal sludge
into municipal wastewater treatment plants. This
has the advantage that it can reduce the volume of
faecal sludge illegally dumped to open drains, water
bodies and open ground but can result in failure of
the wastewater treatment plant (which in turn can
lead to exposure of the downstream consumers to
untreated or poorly treated euent).
The failures are mainly caused by the relatively high
concentration of the faecal sludge (compared to
that of the municipal wastewater) which can lead to
loads which exceed the plant capacity. Faecal sludge
may also include mixed solid waste that needs to be
removed (e.g. with screens) before co-treatment. There
are a number of common problems introduced by co-
treatment, including overloading of solids, chemical
oxygen demand or nitrogen compounds, increasing
the risk of process failure which the treatment
processes can take several weeks to recover.
A preferred approach for co-treatment is to first
dewater the faecal sludge and co-treat the liquid
fraction with municipal wastewater, and co-treat
the solid fraction with the wastewater sludge from
the wastewater treatment technology. This type of
co-treatment has the potential to lead to savings in
both capital and operation and maintenance costs.
However, whether or not co-treatment is suitable will
depend on the quantity and quality of the products
being combined. For example, the constituents of
the liquid fraction from faecal sludge treatment can
be 10 to 100 times more concentrated than the raw
wastewater inuent to a treatment plant. This needs
to be considered alongside the type and design of
the existing technologies, and whether the treatment
plant is operating at capacity. Co-treatment and the
potential advantages and disadvantages of using
dierent technologies is discussed fully in Strande et
al., 2014 (chapters 5 & 10) and Strande, 2017.
3.6 End use/disposal
3.6.1 Definition
End use/disposal refers to the dierent technologies
and methods by which treatment products are
ultimately discharged into the environment, either
as end use products or reduced-risk materials. Where
there is an end use for treatment products by which
(ideally fully treated) wastewater and sludge are
ultimately produced, they can be applied or used;
otherwise, additional risk reducing barriers are needed,
or the products should be disposed of in ways that are
least harmful to the public and environment.
3.6.2 Safe end use/disposal
The key principle at end use/disposal step is reducing
the risks to sanitation workers and wider community
to the remaining pathogen hazards, for example
farmers, who could be at risk from exposure through
ingestion following direct contact with pathogen-
containing compost used for soil improvement. The
wider community also includes the general public
who, where euent is disposed to surface waters
or groundwater, could be at risk from pathogens
through ingestion of contaminated drinking-water,
or from the food chain where contaminated water is
used for irrigation.
Table 3.4 outlines end use products that can be
obtained from the various treatment processes
discussed in Section 3.5.
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WHO GUIDELINES ON SANITATION AND HEALTH
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Table 3.4 includes a description of the end use
products, the resource recovered and the likely
pathogen level of each end use product. Untreated
faecal sludge contains a high concentration of
pathogens but, if buried safely, can be used as a soil
conditioner for fruit trees or forestry provided barriers
are in place on farm to prevent exposure to worker
and local communities and wider communities. For
individual households with a full pit latrine, the pit is
sealed o from human contact with soil. A tree can
then be planted on top, which then benets from the
increased nutrients and organic matter. Deep row
entrenchment is similar but involves the lling of a
trench dug to receive faecal sludge from a number
of containers. Once full, the trench is covered and
sealed, and a row of trees is planted. Burial is only
suitable in locations and the groundwater table is
low enough (refer to section 3.3.2). It is imperative
Treatment product Resource
recovered
End use technology
or product
Technology description Pathogen level in end use product
Untreated sludge -
buried
Organic matter
Nutrients
Soil conditioner
fertilizer
Untreated sludge buried
and used to grow trees
(e.g. arborloo or deep row
entrenchment)
Low to high depending on absorption
characteristics and travel time. The
untreated sludge can contain a high
level of pathogens, but once buried
they may be adsorbed into soil and
inactivated over time.
Dewatered sludge Organic matter Soil conditioner
fertilizer
Dewatered sludge applied to
land
High
Dewatered sludge Energy Incineration Burning of sludge generates
heat for cement kilns.
Low. Ash produced is free of pathogens.
Dried sludge Energy Solid fuel Pellets, briquettes, powder
burned for fuel
Low but only after conversion by
pyrolysis to a pellet, briquette or powder
Dried sludge Materials Building materials Used in the manufacture of
cement, bricks and clay-based
products
Low but only after being subjected to
high manufacturing temperatures.
Compost
(powder or pellets)
Organic matter
Nutrients
Soil conditioner,
fertilizer
Compost, powder or pellets
applied to land
Low
Plants
Food Animal fodder Plants removed from planted
drying beds or wetlands and
fed to animals
Low in plants removed, but care
needed when harvesting, as sludge
and/or euent may contain medium to
high level of pathogens.
Euent Nutrients, water Irrigation water Treated euent applied to land Low to high depending on treatment
technology.
Euent Water Surface water recharge Treated euent disposed or
discharged into rivers, lakes or
oceans
Low to high depending on treatment
technology.
Untreated euent Water Groundwater recharge Untreated euent disposed or
discharged into the ground via
soak pit or leach eld
Low to high depending on absorption
characteristics and travel time. The
untreated euent can contain a
high level of pathogens, but once in
the ground they may be adsorbed
aerobically into soil.
Table 3.4 Summary of established end use products*
Sources: Adapted from Tilley et al. (2014); Strande et al. (2014); and Strande (2017).
* ‘Sludge’ refers to both faecal sludge and sewage sludge.
51
CHAPTER 3. SAFE SANITATION SYSTEMS
Chapter 3
that workers wear PPE and follow SOPs to safeguard
against the pathogen hazard.
Similarly, dewatered faecal sludge may contain a high
concentration of pathogens (especially helminth
eggs, which maintain viability for extended periods)
so should not be applied to land used for food
production and, apart from burial for its nutrient and
soil conditioning value, has little end use potential.
Air-dried faecal sludge may also contain a high
number of pathogens but has a number of uses. It
can be converted for use as solid fuel or building
material. For both uses, the sludge is introduced to a
manufacturing process that destroys the pathogen
hazard, making the end use product safe to handle.
Only compost in which all pathogens have been
completely inactivated can be safely handled by
workers or farmers and applied to land as a soil
conditioner and fertilizer. Nevertheless, all workers
engaged in the manufacture of solid fuels, building
materials or compost from faecal sludge, need to
wear PPE and follow SOPs that will safeguard them
from potential hazards.
Treated euent contains nutrients, which can be
recovered to support plant and crop growth through
use as irrigation water. Wastewater use, whether
treated, untreated, raw or diluted, can be found in
humid and arid climates. However, even treated
euent should not be assumed to be pathogen free.
It should only be applied to land when the risk to
workers and the wider community is well assessed
and managed through multiple barriers adopted
along the sanitation chain (Drechsel et al., 2010).
Where euent is used for irrigation water, a multi-
barrier may include the application of treatment
processes, selecting crops that are high growing and/
or not eaten raw, low contact irrigation methods e.g.
drip irrigation) the use of PPE, and the disinfection,
washing and cooking of produce. The WHO Guidelines
for the Safe use of Wastewater, Excreta and Greywater
(WHO, 2006) provide further guidance. It should
be noted that dierent interventions (barriers) will
have dierent costs, capacity to reduce risks and
requirements in terms of behaviour change (Drechsel
and Seidu, 2011; Karg and Drechsel, 2011).
Similarly, before disposing of effluent to surface
waters or to groundwater, the risks to the wider
community, who may use blended wastewater
euent and river water for irrigation water supplies
and/or drinking or recreational water, should be
considered and necessary control measures put
in place. Importantly, where there is concern that
euent disposal may contaminate drinking-water
supplies, public health and economic trade-offs
between higher levels of wastewater treatment and
improved drinking-water treatment or alternative
sources need to be considered.
Reducing risk at the end use/disposal step
A multi-barrier approach should be used to manage
health risks associated with end use and disposal
(for further details see WHO, 2006 and WHO, 2003).
To reduce the risk, end use/disposal technologies
should be:
• Designed for the local context taking into
consideration the characteristics of the euent or
faecal sludge; local climate and seasonal variations;
and the available energy sources and human
resource capacity.
• Compatible with the preceding treatment
technology and treatment product, as outlined in
Table 3.4.
Adopting the following additional control measures
reduces the risk to workers especially those whose
work involves handling treatment products:
• Wearing of PPE, particularly where using/disposing
of wastewater and, faecal sludge.
• Training on the risks of handling euents or faecal
sludges and on standard operating procedures.
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WHO GUIDELINES ON SANITATION AND HEALTH
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• Regular health checks and preventive treatment
such as deworming and vaccination.
Examples of additional control measures to reduce
the risk to the local community and wider community
where wastewater and faecal sludge are used in
agriculture and aquaculture (WHO, 2006) are:
• Selection of crops that grow high above ground
level (such as fruit trees) or crops not eaten raw
• Low contact irrigation methods (e.g. drip irrigation)
• Withholding periods between application of treated
faecal sludge (e.g. compost) or wastewater and crop
harvesting.
Examples of additional control measures to reduce
the risk to the local community and wider community
at recreational bathing sites (WHO, 2003) are:
• Public notices advising of likelihood of faecal
pollution
• Restricting access and beach closures
In contrast, end use/disposal technologies that do
not adequately reduce the risk are those which result
in untreated euent and/or faecal sludge being left
in the open, disposed in recreational waters, or used
for food production therefore exposing the local
community to pathogens. For instance, in densely
populated urban areas where space is limited, and the
soil is compacted and/or saturated, soak pits, leach
elds or cover and ll approaches are not applicable
as the adsorption process will fail.
Incremental control measures
Untreated faecal sludge and wastewater should not be
applied on land used for food production, aquaculture
or in recreational waters unless accompanied with
additional risk reducing measures. Use of untreated
sludge has been a long-term practice in parts of China,
South East Asia and Africa carries a very high risk from
exposing farmers and their families to pathogens, as
well as others in the wider community from ingesting
pathogens in the food chain. Untreated euent is also
often informally or inadvertently use for irrigation of
food crops. Where this practice is known to happen
and cannot be avoided additional control measures
outlined above should be used while treatment
capacity is established.
Untreated sludges should not be disposed to landll.
However, landfill disposal is preferable to illegal
dumping or use in agriculture as an incremental
measure while treatment capacity is established.
3.7 Applicability of sanitation
systems
The choice of sanitation systems for implementation
should be driven by the specific physical and
institutional context in a given location. This includes
aspects such as population density, ground and
climate conditions and land availability, as well as
human resources and institutional capacity. Changes
to these conditions over the design life of the system
(20 years as a guiding rule) should also be considered,
especially in areas prone to rapid change such as
urbanization.
Table 3.5 sets out key factors aecting the applicability
of the sanitation systems detailed in the sanitation
system fact sheets (Annex 1). Box 3.3 focuses on the
implications of climate change on sanitation systems
and related health outcomes.
53
CHAPTER 3. SAFE SANITATION SYSTEMS
Chapter 3
Table 3.5 Applicability of sanitation systems
Each system is most applicable in the conditions
shown
(Low/Medium/High):
Physical factors Enabling factors
Household level (toilet, containment-storage/treatment, conveyance)
Public level (conveyance,
treatment, end use/
disposal)
Population density is:
Risk to groundwater
used for drinking is:
Water availability is at
least:
Risk of ooding is:
Soil hardness (re:
excavation) is:
Soil permeability is at
least:
Land availability
HR capacity for
infrastructure is at least:
HR capacity for O&M is
at least:
Financial capacity for
infrastructure is at least:
Financial capacity for
O&M is at least:
HR capacity for
infrastructure is at least:
HR capacity for O&M
is at least:
Financial capacity for
infrastructure is at least:
Financial capacity for
O&M is at least:
On-site
sanitation
systems
1: Dry or ush toilet with on-site
disposal
L L L L L M NA L L L L NA NA NA NA
2: Dry toilet or urine diverting dry
toilet (UDDT) with on-site treatment
in alternating pits or compost
chamber
L L L L L M NA L M L L NA NA NA NA
3: Flush toilet with on-site treatment
in twin pits
L L M L L M NA L L L L NA NA NA NA
4: Urine-diverting dry toilet (UDDT)
with on-site treatment in dehydration
vault
L L L NA NA NA NA M M M M NA NA NA NA
On-site
systems
with FSM
and o-site
treatment
5: Dry or ush toilet with pit, euent
inltration and o-site treatment of
faecal sludge
M L M L L M M/H L M L M M/H M/H M/H M/H
6: Flush (or urine-diverting ush)
toilet with biogas reactor and o-site
treatment
M NA M L L NA M/H M M M M M/H M/H M/H M/H
7: Flush toilet with septic tank and
euent inltration, and o-site
faecal sludge treatment
M L M L L M M/H M M M M M/H M/H M/H M/H
8: Urine-diverting dry toilet and
container-based sanitation with o-
site treatment of all contents
M/H NA L NA NA NA M/H L L L L M/H M/H M/H M/H
On-site
systems
with FSM,
sewerage
and o-site
treatment
9: Flush toilet with septic tank,
sewerage and o-site treatment of
faecal sludge and euent
M NA H L L NA M/H H H H H M/H H M/H M/H
O-site
systems
with
sewerage
and o-site
treatment
10: Flush toilet with sewerage and
o-site wastewater treatment
M/H NA H NA NA M/H H H H H H H M/H M/H
11: Urine-diverting ush toilet with
sewerage and o-site wastewater
treatment
M/H NA H NA NA M/H H H H H H H M/H M/H
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WHO GUIDELINES ON SANITATION AND HEALTH
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Box 3.3 Climate change, sanitation and health
Climate change – a change in the state of the climate that can be identied by changes in the mean and/or the variability of its properties and
that persists for decades or longer – exacerbates existing challenges such as rapid population growth, urbanisation, migration, land-use change,
and other forms of environmental degradation. Its potential impact on sanitation systems is extensive. Climate variability and climate change
exacerbate the risks caused by inadequate sanitation by placing considerable strain on sanitation systems, and should be taken into account to
ensure sanitation technologies and services are designed, operated and managed in a way that minimises associated public health risks.
Sanitation is an important vehicle for indirect climate change impacts on health (IPCC, 2014). The health consequences arising from climate
impacts on sanitation systems include increased risk of disease/illness from exposure to pathogens and hazardous substances via environmental
contamination, and/or increased risk of disease/illness resulting from a lack of adequate sanitation where systems have been destroyed or
damaged. Poor and vulnerable groups without access to good quality health care and fundamental public services experience overlapping forms
of disadvantage and are likely to face the worst eects (WHO & DFID 2009).
Adaptation measures for building sanitation system’s climate resilience could be designed under six broad categories: technologies and
infrastructure, nancing, policy and governance, workforce, information systems and service delivery (WHO, 2015). Measures such as data
collection and monitoring systems, disaster response and rehabilitation plans, and behaviour change programmes can support eective adaptation.
Communities, who have existing experience in adaptation for sanitation, should be actively engaged in sanitation system planning processes
(Sherpa et al., 2014).
Table 3.6 sets out potential impacts and examples of adaptation measures available for some key sanitation technologies and sanitation
management systems to improve sanitation systems and in turn help to protect health.
Source: WHO 2018, unpublished.
Sanitation system Potential impact Example adaptation options Overall resilience
On-site systems
Dry and low-ush
toilets
• Reduced soil stability leading to lower
pit stability
• Environmental and groundwater
contamination from toilet ooding
• toilet owners using oodwaters to ush
out pits
• Toilet collapse due to inundation or
erosion
• Line pits using local materials
• Locally adapted toilet designs: raised toilets;
smaller, frequently-emptied pits; vault toilets;
raised pit plinths; compacting soil around
pits; appropriate separation distances; use
of appropriate groundwater technologies;
protective infrastructure around system
• In highly vulnerable areas: low-cost temporary
facilities
• Site systems in locations less prone to oods,
erosion, etc.
• Provide regular, aordable pit emptying
services
• Dispose excreta to secure sewer discharge or
transfer stations
• Promote toilet maintenance, hygiene and safe
behaviours during/after extreme events
High
(Good adaptive capacity
through potential
design changes)
Table 3.6 Examples of climate adaptation options for specic sanitation systems
55
CHAPTER 3. SAFE SANITATION SYSTEMS
Chapter 3
Table 3.6 Examples of climate adaptation options for specic sanitation systems (continued)
Sanitation system Potential impact Example adaptation options Overall resilience
Septic tanks • Increased water scarcity reducing water
supplies and impeding tank function
• Rising groundwater levels, extreme
events and/or oods, causing structural
damage to tanks, ooding drain
elds and households, tank otation,
environmental contamination
• Install sealed covers for septic tanks and non-
return valves on pipes to prevent back ows
• Ensure vents on sewers are above expected
ood lines
• Promote tank maintenance, hygiene and safe
behaviours during/after extreme events
Low to medium
(Some adaptive
capacity; vulnerable
to ooding and drying
environments)
O-site systems
Conventional
sewerage
(combined sewers,
gravity sewers)
• Extreme rainfall events causing
discharge of excess, untreated
wastewater into environment
• Extreme rainfall events causing back-
ooding of raw sewage into buildings
• Extreme events damaging sewers
and causing leakage, resulting in
environmental contamination
• Sea-level rise raising water levels in
coastal sewers, causing back-ooding
• Increased water scarcity reducing
water ows in sewers, increasing solid
deposits and blockages
• Use deep tunnel conveyance and storage
systems to intercept/store combined sewer
overow
• Re-engineer to separate stormwater ows
from sewage
• Where feasible, decentralize systems to
localize/contain impacts
• Provide additional storage for stormwater
• Use special gratings and restricted outow
pipes
• Install non-return valves on pipes to prevent
back ows
• Where appropriate, install small-bore or other
low-cost options to reduce costs of separate
systems
• Promote hygiene and safe behaviours during/
after extreme events
Low to medium
(Some adaptive
capacity; vulnerable
to reduced water
availability and
ooding of combined
sewers)
Modied sewerage
(e.g. small-bore and
shallow sewers)
• Floods and extreme events damaging
sewers, especially shallow sewers
• Small-bore sewers: damage to pipework
infrastructure introducing soil to system
and causing solid deposits/blockage
risks
• Shallow sewers: increased water
scarcity reducing water ows in sewers,
increasing solid deposits and blockages
• Install non-return valves on pipes to prevent
back ows
• Construct simplied sewer networks to
withstand ooding and otation, or shorter
networks connected to decentralised
treatment facilities to reduce sewer overload
and failure
• Promote hygiene and safe behaviours during/
after extreme events
Medium
(Some adaptive
capacity; vulnerable to
ooding, though less
vulnerable to reduced
water availability than
conventional sewerage)
Faecal sludge
treatment
• Extreme weather events or oods
destroying/damaging wastewater
treatment systems, causing discharge
of untreated sewage and sewerage
overow and environmental
contamination
• Extreme rainfall damaging waste
stabilisation ponds
• Extreme events damaging low-
lying treatment plants, causing
environmental contamination
• Increased water scarcity causing
obstruction, reducing capacity in rivers
or ponds that receive wastewater
• Install ood, inundation and run-o defences
(e.g. dykes) and undertaking sound catchment
management
• Invest in early warning systems and
emergency response equipment (e.g. mobile
pumps stored o-site, non-electricity based
treatment systems)
• Prepare a rehabilitation plan for the treatment
works
• Where feasible, site systems in locations less
prone to oods, erosion, etc.
• Provide safe means for manual emptying of
sludge with low moisture content
Low to medium
(Some adaptive
capacity; vulnerable to
increases/ decreases
in water availability;
reduced carrying
capacity may increase
sludge treatment
requirements)
56
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 3
Sanitation system Potential impact Example adaptation options Overall resilience
Wastewater reuse
for food production
• Increased water scarcity leading to
increased reliance on wastewater for
irrigation purposes
• Without adequate wastewater
treatment, increased reuse can
expose populations (farmers, their
communities and consumers) to health
hazards including pathogens, chemicals,
and anti-microbial resistance
• Include climate change and variability in
assessing, monitoring and establishing control
measures for wastewater management
• Improve enforcement/ incentives for following
regulations for wastewater reuse
• Improve crop selection, irrigation type,
withholding times
• Ensure sanitation worker vaccination and
treatment
• Promote hygiene practices and use of personal
protective equipment
Table 3.6 Examples of climate adaptation options for specic sanitation systems (continued)
Sources: adapted from Howard & Bartram, 2010; Charles, Pond & Pedley, 2010.
57
CHAPTER 3. SAFE SANITATION SYSTEMS
Chapter 3
References
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Banks D, Karnachuk OV, Parnachev VP, Holden W, Frengstad
B (2002). Groundwater contamination from rural pit latrines:
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Blockley DI (2005) The new Penguin dictionary of civil
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Cairncross S, Feachem, R. G. (2018). Environmental health
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Charles K, Pond K, Pedley S (2010). Vision 2030: The resilience
of water supply and sanitation in the face of climate change:
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Coe O, Nikiema J, Impraim R, Adamtey N, Paul J, Koné D (2016).
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Reuse Series 3).
Drechsel P, Scott CA, Raschid-Sally L, Redwood M, Bahri A (eds.)
(2010). Wastewater irrigation and health: Assessing and mitigation
risks in low-income countries. Earthscan-IDRC-IWMI, UK.
Drechsel P, Seidu R (2011). Cost-eectiveness of options for
reducing health risks in areas where food crops are irrigated with
wastewater. Water International. 36 (4): 535-548.
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development of on-site sanitation. World Health Organization,
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on groundwater quality: A systematic review. Environ Health
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Howard G and Bartram J (2010). Vision 2030: The resilience
of water supply and sanitation in the face of climate
change:Technical report. Geneva: World Health Organization.
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health: impacts, adaptation, and co-benets. In: Climate Change
2014: Impacts, Adaptation, and Vulnerability. Part A:Global
and Sectoral Aspects. Contribution of Working Group II to
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on Climate Change [Field CB, VR Barros, DJ Dokken, KJ Mach,
MD Mastrandrea, TE Bilir, M Chatterjee, KL Ebi, YO Estrada,
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Mastrandrea, and L. White (eds.)]. Cambridge: Cambridge
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improvement of the service to users. Geneva, Switzerland.
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wastewater utilities and for the assessment of wastewater
services. Geneva, Switzerland.
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on-site domestic wastewater service. Geneva, Switzerland.
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30500 – Non-sewered sanitation systems — Prefabricated
integrated treatment units — General safety and performance
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Vulnerability and adaptability of sanitation systems to climate
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Management: Systems Approach for Implementation and
Operation. IWA Publishing, UK.
Strande L (2017). Introduction to faecal sludge management: an
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Tayler K (2018). Faecal Sludge and Septage Treatment; A Guide for
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Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib R, Zurbrügg
C (2014). Compendium of Sanitation Systems and Technologies.
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(EPA).
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Building Climate Resilient Health Systems. Geneva: World Health
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Manual for safe use and disposal of wastewater, greywater and
excreta. WHO, Geneva, Switzerland.
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Climate Change, March 2018, Geneva.
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2030 : the resilience of water supply and sanitation in the face of
climate change. Geneva : World Health Organization.
59
CHAPTER 4. ENABLING SAFE SANITATION SERVICE DELIVERY
Chapter 4
4.1 Introduction
Safe sanitation systems require input from a range
of stakeholders, but national and local government
are central to their effective planning, delivery,
maintenance, regulation and monitoring. This
chapter presents an implementation framework for
sanitation interventions, describing the components
within national and local governance functions and
examining who is responsible for them.
4.2 Components of an
implementation framework
Sanitation services – ranging from support for self-
provision of simple toilets to the construction and
management of complex sewerage systems with
technically advanced treatment facilities – must
be accessible to people where they live. Thus, the
focus for implementation is at the local level. Local
government usually has the responsibility to ensure
adequate levels of sanitation but, even where it does
not, local oversight and coordination are essential to
ensure that all the complementary components of
the service chain function eectively together.
Sanitation service providers may be formal or
informal private enterprises, publicly or privately-
owned utilities, local government departments, or
(in most cases) a combination of these. The services
themselves can be broadly divided into three
categories, according to how they are delivered:
• Individual services, such as toilet construction,
hardware supplies, removal of faecal sludge or
containers, and provision of public toilets. These
provide direct benets to users as well as improving
public health at the community level. These
services are typically suitable for provision by small
businesses and they may be commercially viable;
however, poorer households are likely to need
subsidization to access them.
• Shared services, which include operation and
maintenance of sewerage and drainage systems
and faecal sludge treatment. These are delivered
downstream of users, producing public health
benets to the community, and may not be possible
or fair to nance entirely by direct user fees. They
are usually delivered by local authorities or utility
companies but may also be subcontracted to the
private sector and may be funded through, for
example, local tax revenue, cross subsidy from water
supply and government subsidies.
• Infrastructure development, comprising the design
and construction of sewerage, drainage, faecal
sludge transfer stations and faecal sludge and
wastewater treatment plants, primary water supply
systems or slum upgrading. These also provide public
health benets to the community, but require major
investment, which may require recourse to high level
(national, state, regional or provincial) authorities or
external nancing.
Chapter 4
ENABLING SAFE SANITATION
SERVICE DELIVERY
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WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 4
Sanitation services should fit together to ensure
coherent sanitation service chains (as illustrated in
Figure 4.1) that safely manage excreta from generation
to treatment and safe disposal or use. This demands
technical alignment (e.g. the design of pits and emptying
equipment so that they work together to enable the
hygienic removal of faecal sludge) and coordinated
planning, so that all components of the service chain are
in place (e.g. faecal sludge treatment plants are present
and functioning to deal with collected sludge).
The main components and responsibilities for
sanitation implementation are outlined in Figure 4.2
and below.
The national government role includes the setting of
standards and targets and the empowerment of local
authorities and other agencies to deliver and oversee
sanitation services. It is also responsible to ensure
equality in access to services, in line with human
rights and the SDGs. Government should provide
policy guidance, rules and incentives and promote
the development of adequate capacity to deliver
sustainable, aordable and safe managed sanitation
services, and to provide a favourable environment
for incremental improvement to sanitation services,
for instance through scaling up or formalising local
and pilot initiatives. Coordination, accountability and
regulatory mechanisms are also needed, so that the
interdependent services required for the delivery of
safe sanitation systems function without interruption,
and according to the prescribed standards. National
authorities guide and support local government and
may support the development of major infrastructure.
Figure 4.1 Categorization of sanitation services
Pit latrine (dry or ush)
Sewer network, pumping stations
SHARED SERVICES*
Provided at community/public level
Infrastructure development
• Faecal sludge haulage and treatment
• Sewerage construction, O&M
• Drainage construction, O&M
• Solid waste management
INDIVIDUAL SERVICES*
Provided to individual users but with public benets
• Materials supply
• Toilet construction
• Public toilets
• Desludging
Sewage
treatment
plant
Use
Agriculture/
horticulture
Aquaculture
Energy
Groundwater
recharge
Disposal
River or ocean
Landll
Containment
storage/treatment
Septic tank/pit/
holding tank
Vacuum truck
Primary emptying Transfer
Conveyance –
emptying/transport
Treatment
End use/disposal
Flush toilet
Toilet
Faecal
sludge
treatment
plant
*Delineation of individual services and shared services in this diagram does not signify who should bear the full cost of services
61
CHAPTER 4. ENABLING SAFE SANITATION SERVICE DELIVERY
Chapter 4
Local government is responsible for (or oversees)
service provision and is accountable for this both to the
national government and to local communities. It has
direct authority over providers of shared services while
overseeing and maintaining dialogue with providers
of individual services, whose primary relationship
is directly with users. Critically, it also engages with
user communities, to negotiate a balance between
community needs and their willingness and ability to
pay for services, and to encourage communities to play
their role in achieving eective sanitation.
4.3 Policy and planning
4.3.1 Policy
Governments need to enact policies to ensure that
the entire population within their jurisdiction have
access to safe sanitation services, that can be achieved
through stepwise targets or milestones for incremental
improvements (Box 4.1). Existing policies, regulation
and legislation should be regularly reviewed to
ensure they do not include provisions that impede
sanitation improvements; for instance, provisions
Function addressed in these guidelines; Function not addressed in these guidelines; Function with primary role for environmental health sta.
This gure indicates how the dierent levels of the implementation framework interact with each other, and the services and infrastructure that they should deliver.
National government functions
Policy and coordination (Section 4.3)
Planning (Section 4.3), monitoring and nance (Section 4.5)
Legislation, regulation, standards and guidelines (Section 4.4)
Capacity building and technical assistance (Section 4.6)
Local governance functions
Urban planning or district level (land use, water supply and drainage, transport and communications,
solid waste management)
Planning and coordination (Section 4.3)
Housing policy and tenure arrangements
Support to development of local services
Local level legislation and enforcement (Section 4.4 and 4.6)
Promotion and monitoring of sanitation and hygiene (Section 4.6, 4.7 and Chapter 5)
Community engagement functions
Planning and setting service levels (Section 4.6)
Sanitation behaviour change and marketing (Section 4.9 & Chapter 5)
Individual services (Chapter 3)
Toilet construction
Hardware supplies
Sewer connections
Sludge & container removal
Public toilets
Shared services (Chapter 3)
Faecal sludge treatment
Sewerage operation
Drainage management
Infrastructure (Chapter 3)
Sewerage
Wastewater and faecal sludge
treatment plants
Drainage
Primary water supply
Slum upgrading
Figure 4.2 Implementation framework for sanitation
62
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 4
against providing services in informal settlements, the
outlawing of pit latrines where no realistic alternative
exists in the medium term, or legal/regulatory
impediments to safe use of treated wastewater, excreta
and greywater within other sectors’ policies, regulation
and legislation (e.g. agriculture, food safety).
Ensuring sanitation for all is challenging and the
approaches adopted need to be tailored to the
conditions prevailing in each specic situation. This
requires the concurrent use of a range of dierent
sanitation systems and services (see Chapter 3), and
behaviour change strategies (Chapter 5). Policies must
be practical and feasible, preferably based on what is
found to work in practice in a given context, rather
than an ideal vision or imported approaches from a
dierent physical, economic and social environment.
A good approach is to develop national policy
referencing existing initiatives that are working well
in parallel with innovation in improving sanitation
at local level, so that each can inform the other. The
policy formulation or revision process should include
a wide-ranging and inclusive stakeholder dialogue
to develop consensus between the many actors
involved in sanitation and allow continued review
and course-correction where necessary.
Box 4.1 Setting targets
National sanitation policies and strategies should include clearly dened objectives based on a systematic analysis of the sanitation situation
which includes an understanding of how excreta ow from point of generation to end use or disposal and the associated public health risks.
• As a rst step the multi-stakeholder platform should complete a situational analysis of existing legislation, policies and practices, as well as
an assessment of levels of access to and overall eectiveness of sanitation in dierent contexts and geographic areas.
• Sanitation standards and targets should be set in order to improve public health and in alignment with human rights principles (Box 1.2).
• Standards for sanitation should be clearly dened based on a systematic analysis of public health, sanitation access and behaviours, legislative,
policy and regulatory landscape, institutional roles, nancing and capacity.
• Targets, which are stepping stones towards meeting standards, may be mid- or long-term based on the context and available resources to
allow for incremental improvements and increasing equality in access to services. Long-term planning should identify how meeting targets
ultimately leads to the attainment of all sanitation standards for universal access to sanitation and improving service levels for the poorest,
disadvantaged and most marginalised groups.
Very few governments can immediately achieve the standards that they have set. The process of target setting recognizes this, giving opportunity
to prioritize where eorts should be placed to reach the standards and comply with human rights principles of equity and non-discrimination.
Targets may be national, and there may also be targets set at the regional or local level, generally set by the relevant level of local government.
Targets should include publication of plans and budgets, so that people know how and when they can expect services to improve. National
sanitation targets should be based on the results of the situational analysis.
Targets or milestones should dene priorities, be time-bound and, as far as possible, measurable, so that those responsible for attaining the
targets can be held accountable. These can be dened according to many criteria, including targets based on health, targets for achieving service
provision for particular population groups – particularly poor and disadvantaged groups, targets for types of service provision, budgetary targets,
targets for particular behaviours, targets for achieving institutional arrangements or for regularity of monitoring.
Most countries have targets for dierent types of service, technology and system. In order to ensure that they are relevant and supportive,
representative scenarios should be developed, including description of assumptions, management options, control measures and indicator systems
for verication. These should be supported by guidance addressing the identication of national, regional or local priorities and incremental
implementation, thereby helping to ensure that best use is made of available resources. Targets for realising the policies and standards for
sanitation must be established by a high-level authority responsible for sanitation and health in consultation with other stakeholders, including
local authorities, sanitation service providers and local communities.
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CHAPTER 4. ENABLING SAFE SANITATION SERVICE DELIVERY
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4.3.2 Planning sanitation systems
To formulate inclusive, equitable and practical
solutions, it is essential to understand the existing mix
of sanitation systems in use, and to plan how that mix
should change over time as progress is made towards
the targets for sanitation and hygiene established in
local and national policies. The mix and targets are
dierent for dierent types of community (e.g. urban
and rural populations), and intermediate as well as nal
targets should be set for each (Box 4.1). Figure 4.3 is an
example of how technology targets can be visualised,
showing phasing out of unsafe sanitation systems to
achieve universal access to safe systems over time.
A consequence of this approach is the incremental
improvement of sanitation in dierent places and at
dierent times. Interventions can be targeted and
sequenced to maximize their positive impacts on
public health and well-being. This can deliver much
greater improvements in the short to medium term
than the master planning approach that sets long-
term targets but tends to miss intermediate steps.
The time frame to achieve sanitation targets typically
falls well beyond the normal time horizons of
electoral cycles or externally funded projects (i.e.
3–5 years). Sanitation planning, therefore, should
be institutionalized and integrated into government
planning, budgeting and financing systems.
Establishing specic budget lines, funding windows
and expenditure codes for sanitation at central and
local government levels can help achieve this. An
adaptive approach to planning can be applied,
which includes formulation of long-term policies and
strategies; continuous links between planning and
implementation; regular monitoring, evaluation and
ongoing learning from both successes and failures;
and continuous dialogue with intended beneciaries
to adjust activities to their needs (Therkildsen, 1988).
Figure 4.3 Example of phasing out unsafe sanitation over time
0%
20%
40%
60%
80%
100%
Open defecation
Manual emptying
Non-sewered, emptied
but not treated - sludge and
liquids discharged to open
ground or surface water
Pits, covered and built
new when full
Non-sewered (e.g. pits, septic tanks,
containers) with safe conveyance and
treatment
Centralised and decentralised
sewerage with treatment
Time
Shared
Leaking and untreated sewerage
64
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 4
4.4 Legislation, regulations,
standards and guidelines
4.4.1 Scope
The legislative framework for sanitation should cover
the whole service chain, including both sewered
and non-sewered sanitation, to enable the best
use of public funds, achievement of standards and
attraction of potential service providers.
Ensuring adequate standards for sanitation is a
government function. Standards and regulations
should avoid prescribing specic technologies or
systems for particular situations as their suitability
can be aected by a multitude of factors. In addition,
legislation evolves more slowly than technologies
and therefore can impede innovation. Instead,
standards and regulations should set out what
level of performance is required to achieve a safe
Table 4.1 Areas that may require legislation and regulation
Step in chain Examples of sanitation aspects covered by legislation and regulation
Toilet/
containment-storage/
treatment
Toilet:
• Minimum requirements for toilet room/superstructure (household and shared/public)
• Accessibility to toilets for users with disabilities (shared/public/institutions))
• Stance/user ratios for school, institutional and other public toilets (shared/public)
• Handwashing and water supply facilities for school, institutional and public toilets (shared/public)
• Standard of pit latrine slabs and pour ush pans (household and shared/public)
• Maximum toilet ush volume (in water scarce areas) (household and shared/public)
Containment - storage/treatment:
• Exclusion of insects and other animals from faecal material
• Access to pit or tank for emptying
• Design of septic tanks
• Management of liquid euent from latrine pits and septic tanks
• Registration of on-site facilities
• Standards for euent discharged to sewers
• Safety and performance of container and mobile toilet units
Conveyance Emptying:
• Obligation for premises to be connected to sewer system if available
• Taris for disposal of sewage and faecal sludge at treatment plants
• Siting of pits and tanks so they can be emptied
• Pedestrian and trac safety during pit and septic tank emptying operations
• Control of nuisances and spillages when emptying faecal sludge
• Service standards for container and mobile toilets
Transport:
• Frequency of sewer blockages and overows
• Time taken to resolve sewer blockages and overows
• Rectication of damage caused by faulty sewers and pumping stations
• Containment of faecal sludge in transport equipment and transfer facilities
• Operational and worker health and safety
Treatment • Control of public and service provider access to treatment facilities
• Control of nuisances (odours, ies, noise etc.) from treatment facilities
• Designated facilities and opening hours for faecal sludge dumping
• Liquid euent standards
• Standards for sludge disposed of (if not used)
• Certication of proprietary systems
• Operational and worker health and safety
End use/disposal • Standards for sludge products, categorized by type of safe use
• Standards for use of other products derived from faecal waste
• Operational and worker health and safety
65
CHAPTER 4. ENABLING SAFE SANITATION SERVICE DELIVERY
Chapter 4
sanitation service chain and allow exibility on how
it is achieved.
The provision of sanitation services can include both
the public and private sector; while service providers
of all types should work to the same standards,
different regulatory mechanisms may be needed
for dierent service delivery models. The standards
for sanitation provision can be included in local
legislation and by-laws and/or in national legislation.
The decision as to the appropriate approach depends
on country-specic factors.
The legislative and regulatory framework should reect
the national interpretation of safe management at each
step of the sanitation service chain (see Chapter 3 and
Table 4.1) and could include minimum requirements for
toilets, septic tanks, service standards for container and
mobile toilets and aspects related to occupational health
and safety. It should also dene roles and responsibilities
and minimize overlapping mandates.
In addition, it may be useful to develop national
guidance on sanitation systems covering the whole
service chain and criteria for their selection. Each country
has dierent needs, so what is nally included should
be determined by a policy dialogue that recognizes
that everyone is entitled to sanitation services that
are accessible, safe to use and protective of health,
aordable and acceptable (De Albuquerque, 2014).
These and any other sanitation attributes selected
should be controlled primarily according to public
health criteria. However, they also have implications for
the environment and public amenity, and for the cost,
aordability and equality of access to sanitation services.
The circumstances of each country (or local government
jurisdiction exercising legislative or regulatory powers)
dictate how these factors are weighted.
A key area for regulation that applies across the
whole service chain, is fees and taris for services
delivered by utilities, public institutions or entities
under their control (e.g. treatment plants under lease
or concession arrangements). These may include
sewerage connection fees, fees for use of public or
shared toilets, sewerage taris, fees for pit emptying
by utilities or public institutions, faecal sludge tipping
fees, etc. They should be regulated at price levels that
ensure that sanitation services are accessible to all,
including poor households, while remaining nancially
viable for private or commercially managed operators.
4.4.2 Risk assessment and management
A risk assessment should guide sanitation
interventions to ensure sanitation protects public
health by managing the risks arising from excreta
management along the sanitation chain from the toilet
to nal disposal or use. The risk assessment should
identify and prioritize the highest risks and use them
to inform system improvements through a mixture of
controls along the sanitation chain. Improvements may
include technology upgrades, improved operational
procedures and behaviour change.
In the context of regulation and standards the focus
should be primarily on specific components of
sanitation service chains, but it may also extend to
complete sanitation systems or parts of them, for
example sanitation by-laws or planning regulations.
Public or environmental health sector sta (see Section
4.6) are usually be best placed to identify and analyse
the sanitation issues requiring attention, but they will
need to work with all relevant stakeholders (such as local
authorities, wastewater utilities, sanitation enterprises,
the institutions in charge of environmental and building
standards, farmers and civil society organizations) to
ensure the completion of a robust risk assessment and
formulation of realistic risk management options that
can then be translated into standards and regulations.
The rst step in the process is thus the creation of a
stakeholder group, with leadership assigned to the
group member with the best mix of authority, and
organizational and interpersonal skills.
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WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 4
Risk assessments should be based, as far as possible,
on actual conditions, rather than on assumptions
or information imported from elsewhere. Frontline
government sta such as public health or agricultural
extension workers, students, community leaders and
community-based organizations can be eective in data
collection if well organized, incentivized and supervised.
4.4.3 Regulatory mechanisms
The various steps in sanitation service chains dier
in their nature, requiring a corresponding range of
regulatory mechanisms. Ways in which the dierent
steps can be regulated are illustrated in Figure 4.4.
The various mechanisms are highlighted in bold in
the following text to facilitate cross-referencing.
Additionally, because sanitation cuts across many
sectors, relevant legislation and regulation is also
widely scattered and elements may be found under:
• local government public health, occupational
health and safety, environmental, water resources
and consumer protection legislation;
• Legislation and regulations covering agriculture,
energy and food safety with safe use of faecal sludge;
• local by-laws;
• building and planning codes/standards;
• public utility regulation; and
• others.
Considerable effort may be needed to identify,
update and align all the necessary elements,
ensuring that they adequately address safe sanitation
services, and conicts and contradictions need to
be resolved. It may not be possible to remove all
legislative and regulatory overlaps and discrepancies,
and coordination should ensure that these do not
create unnecessary barriers to service improvements.
Goods and infrastructure can be regulated under
the relevant national technical standards, and
procedures for preparing and implementing such
regulation are usually clearly dened. However, where
illegal or informal settlements are common, these
Figure 4.4 Sanitation service chain regulatory mechanism options
Toilet/Containment
and on-site treatment
Conveyance Treatment End use/disposal
Planning &
Building Regulations
Re-use Standards
(all use types)
Utility Regulation
Treatment Standards (liquid euent and sludge)
Licensing
Occupational Health and Safety Regulations
Technical
Standards
Consumer
Protection
National guidelines Licensing
Environmental Health Regulations (Public Health and Nuisance Abatement)
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CHAPTER 4. ENABLING SAFE SANITATION SERVICE DELIVERY
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systems may break down. For example, the quality of
a toilet cannot be regulated if the whole premises are
considered illegal, and the approval of a component
of the premises might be taken to imply that the rest is
legal, when it is not. In such cases it may be possible to
use public health or nuisance abatement legislation
(which focuses on the eect of an inadequate toilet,
rather than the toilet itself), supported by national
guidelines instead of legal standards.
On-site sanitation facilities present a particular
challenge as they are often individually built. Where
industrially produced components (e.g. precast or
moulded plastic septic tanks) are used, they can
be covered by national technical standards or
consumer protection legislation. In premises with
formal tenure, contextualized building regulations
and their associated inspection mechanisms are a
good means of controlling the quality of installation
and construction. Such regulations should specify
the format and volume of the facility as a function of
the number of users, approved methods of managing
the liquid euent, provision for access by desludging
equipment (including access into the tank or pit) and
accessibility from the road. Where there is no formal
tenure, or in rural areas where a self-supply approach
is being implemented, national guidelines covering
the same aspects are more appropriate. These should
distinguish between facilities which will be covered
over and replaced when full, and permanent facilities
which will be emptied. The regulations and guidelines
should allow for various types of toilet that may be
assessed as adequate by the environmental health
authorities (see Section 4.6).
Treatment standards for liquid euent and sludge
discharges usually have a clearly dened basis in law
and institutional procedures for setting and enforcing
them. It may be necessary to allow a dened period of
time to achieve the standards and also to set one or
more incremental standards to promote incremental
improvements, so that high standards are seen as
attainable. Standards should also be developed for
each intended use or disposal environment rather than
a blanket standard applied to all treatment facilities.
Unintended euents (such as leakages from septic
tanks, latrine pits or sewage pumping stations) should
be covered by public health or nuisance abatement
legislation, which should be reviewed and, if necessary,
amended to cover such cases.
The regulation of services can be complex, and depends
on the nature of the entity providing the services.
When it is a national or local government department
(i.e. acting to both regulate and provide services) it
is unlikely to be feasible to regulate it (as that would
require one governmental body taking legal action
against another), and applying legal remedies such
as nes may be counterproductive. Specic legislation
and administrative mechanisms may be needed in
such situations. If the service provider is a public utility,
there should be specic regulatory arrangements in
place which can be updated and expanded as needed.
If a private enterprise provides services on behalf of a
utility, it can be regulated through a contract or service
level agreement with the utility.
Where the private sector provides services
independently, dealing directly with customers,
a licensing arrangement may provide a suitable
regulatory mechanism. This should specify service
standards, an inspection regime and remedies for
failure to meet the conditions. It may also (but not
necessarily) specify maximum fees, or an equitable
tari structure covering one-time (e.g. connection
fees) and regular services. Separate licensing
arrangements may also be a good option for private
sector operators selling processed sludge products
(solid or liquid) to ensure that adequate pathogen
control measures are in place. Further protection,
where the products are used in agriculture,
horticulture, aquaculture, groundwater recharge and
energy can be provided by standards for safe use.
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Efforts should be made to simplify and unify the
licensing arrangements; for instance, faecal sludge
emptying and transportation businesses may be
required to have numerous licences, such as a business
licence issued by the local government, an operational
licence issued by the public health department and a
hazardous waste transportation licence issued by the
environmental agency. This adds complexity and cost,
and may discourage potential service providers from
entering the business.
Sanitation workers are exposed to particular health
risks, and require specic measures to ensure their
health and safety. These should include periodic health
checks, vaccinations and treatment (e.g. deworming),
medical insurance (if available), PPE (Chapter 3), as
well as training on standard operating procedures
(Chapter 3). The onus should be on employers to
provide all of these, and these requirements should
be included in the regulatory arrangements to which
employers are subject. Compliance should be veried
by health sector personnel (e.g. environmental or
occupational health sta).
4.4.4 Enforcement and compliance
Achievement of compliance with standards and
regulations requires a broad approach that includes
a mix of incentives, promotion and sanctions. Non-
coercive means, such as information dissemination,
technical assistance, promotion and awards should be
used in the rst instance. Tax and other scal incentives,
or privileged access to special services (such as loan
guarantees for equipment renovation and purchase)
can be economically ecient in some circumstances.
Enforcement through legal sanctions is a last resort and
this should be applied only when non-coercive options
have failed. The legislation should be designed with a
series of escalating stages to allow an oender to rectify
the infraction before any penalty is nally imposed.
When developing regulatory systems, better results
are often achieved when it is done in partnership
with those being regulated. In this way it is possible to
utilize their experience of what is practical and feasible.
Such partnering may appear counter-intuitive (service
providers might be expected to resist regulation) but,
in most cases, the advantages gained from being
formally recognized outweigh any disadvantages that
might arise from well-designed regulation.
Sanitation standards need to be monitored and
enforced. The capacity for inspection and prosecution
needs to be assessed to determine whether it is
sucient to cope with the predicted demands. A risk
assessment approach (Section 4.4.2) can be useful
in making these decisions, so that the amount of
resources required to deliver public health outcomes
is clear. Capacity issues may go beyond the public
health system to the legal system and should be
reviewed together. Related to this is the importance
of invoking regulatory actions, which should lead to
an instruction to desist from using a certain type of
infrastructure or practice, only if there is a realistic
alternative. For instance, banning a certain type of toilet
is counterproductive if it results in open defecation.
National guidelines should be produced advising
how to apply enforcement, and training provided on
how to manage legal proceedings, particularly the
collection and presentation of evidence. Responsible
managers should review the enforcement activity
and report on it annually, highlighting any sanitation
issues that arise, and checking that it is not being
applied abusively.
4.5 Roles and responsibilities
4.5.1 Coordination and roles
Sanitation spans many sectors and requires
coordinated action by many stakeholders, and
complete responsibility cannot be assigned to one
ministry or agency. This means that it is necessary
to establish a multi-sectoral platform for dialogue
between the main stakeholders and to develop and
oversee coordinated plans of action. This requires
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specic administrative support, such as a secretariat,
to function eectively. Experience has shown that
this is best situated in a senior ministry or bureau with
a governance rather than a service provision role,
such as planning, nance, or the prime minister’s or
president’s oce.
Political leadership for the coordination and
implementation of safe sanitation systems and services
is also needed, by a minister from one of the principal
ministries involved or another senior political gure
ready to assume the challenge of driving progress on
sanitation. The secretariat should prepare information
(possibly with support from development partners)
to help in making the case for allocating resources
to sanitation. A short- to medium-term strategy with
feasible interventions and potential evidence based
quick wins, should also be outlined, so that visible
action can follow swiftly from political decisions.
The prepared material should be a consistent set of
relatively simple messages, which could include:
• excreta ow diagrams (e.g. Figure 3.1) and diagrams
of the sanitation service chain (e.g. Figure 1.1);
• contextualized evidence on implementation
approaches that work;
• locally relevant statistics on the burden of a range
of sanitation-related diseases and conditions (e.g.
diarrhoeal disease outbreaks, levels of stunting,
prevalence of diseases such as soil-transmitted
helminth infections); and
• estimates of the economic impacts of sanitation,
both on productive sectors such as tourism,
environment, attraction of employers, etc., and on
lost productivity and economic losses to households
due to illness and opportunity costs.
The composition of the multi-sectoral sanitation
platform depends on how responsibilities are
distributed among ministries and public agencies.
Institutions that may be involved include ministries
of education, environment, nance, health, housing,
justice, local government, planning, public works,
water, the national statistics office, major utilities,
representation of municipal and local governments,
civil society and others. The process of joint sector
planning and the alignment of the institutions’ own
internal plans relevant to sanitation are likely to identify
gaps and overlaps to be rectied. This may need to be
reected in policies, memoranda of understanding or
other ocial instruments over the medium term, but
it should be possible to reach informal agreements to
enable progress over the short term.
In some urban areas, sewerage may be managed
by a utility, while non-sewered sanitation is the
responsibility of local government. Such fragmentation
of responsibility for sanitation can lead to poor planning,
exclusion of poorer communities and, ultimately,
reduced cost-effectiveness. Where an adequately
performing utility company exists, consideration should
be given to extending its mandate to cover both
sewered and non-sewered sanitation.
Responsibility for running sanitation facilities within
public buildings (such as schools, health centres,
markets, transport terminals, prisons, etc.) should be
assigned to the institution responsible for the premises
in question, rather than the ministry responsible for
the water supply and sanitation sector. This should
involve the clear assignment of responsibility and
finances for building and maintaining toilets to a
department, section or unit within the responsible
institution. Standards (such as user ratios), designs and
management models should be developed within the
institutional unit in collaboration with the health, water
supply and sanitation, and public works sectors. These
institutional units should ensure that supervision
and technical assistance in building and managing
sanitation facilities are provided to the local sta who
are directly responsible for them.
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4.5.2 Accountability and finance
Strong accountability frameworks are essential to
ensure that safe sanitation services are maintained.
This can be achieved by linking sanitation to the
government budget process, since public funds
are tracked, and the results of their use need to be
demonstrated. The linkage may be made through
general allocations to local government which are
calculated partly on the basis of indicators, one or
more of which can be made to reflect sanitation
performance, and/or the adoption of specic good
practices. Alternatively, or additionally, dedicated
budget lines and funding windows for sanitation can
be established.
The pivotal role of local government must be
recognized, and resources and technical assistance
should be channelled to them. Only a small portion of
national functions should be retained at national level.
In some countries, local government may wholly
or partially delegate responsibility for water and
sanitation to a national or local utility company, and
specic arrangements may be needed to channel such
support to a utility. Where a utility is required to take
on non-sewered sanitation systems, sucient time
should be allowed for the transition to be made to
avoid damaging the commercial viability of the utility.
The institutions involved in sanitation need stang
and training in accordance with their agreed roles. This
may mean additions and/or changes to government
schemes of service and the allocation of budgets for
training and peer-to-peer learning.
An additional (and complementary) accountability
mechanism to budget linkage is to establish sanitation
as an explicitly identied function of local government,
to be reported to the layer of government immediately
above (e.g. state or province). This type of accountability
is driven principally by plans and targets, which should
be regularly updated if they are to be meaningful.
Accountability can be further strengthened by putting
the plans, targets and reports on them into the public
domain, were they can be scrutinized by citizens,
organized civil society and the media.
Whatever accountability mechanism is used, eective
monitoring metrics and indicators are needed that
measure progress on all steps of the sanitation
service chain. Wherever possible, definitions and
monitoring elements should align with nationally
relevant elements of global norms (Chapter 3) and the
subset used for global monitoring to streamline both
the national and global monitoring processes. This is
discussed further in the Section on monitoring (4.6.3).
In addition to tracking outputs, it is also important to
ensure that elements which allow progress are in place
(these are discussed in more detail in Sections 4.6 and
4.7), and these include the existence, at local level, of:
a) plans showing time-bound targets for the various
components of a mix of sanitation services
covering all people and settings, associated with
realistic budgets;
b) a functioning mechanism for coordinating
sanitation across the relevant sectors;
c) an active programme of sanitation and hygiene
behaviour change and monitoring and community
consultation on sanitation (Chapter 5); and
d) service providers with sucient competence and
capacity to meet community sanitation needs.
Sanitation plans should be prepared by the responsible
authority to ensure ownership, feasibility and relevance
to local conditions.
4.6 Environmental health authorities
and their role in sanitation
Ministries of health normally have a team dedicated
to environmental health. Environmental health covers
topics such as drinking-water safety, sanitation, air
pollution, occupational health and chemical safety.
Environmental health departments need to engage
with many more actors outside the health sector to
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achieve their public health objectives than other
departments within ministries of health.
Environmental health authorities require a broad
range of skills encompassing health, biology,
engineering, law, sociology and more to fulfil
the environmental health functions within the
framework of health sector functions (Rehfuess, Bruce
& Bartram, 2009). Dedicated posts for sanitation
managers reecting their specialist knowledge may
be useful and one role could include brieng other
environmental health staff on the importance of
sanitation, with an emphasis on the service chain and
an inclusive community-wide approach.
Ministries should ensure that environmental health
has a sucient status with the ministry that reects
the foundational preventive health functions of the
discipline that underpins progress on many health
sector objectives.
The principal functions of the environmental health
authorities with regard to sanitation are described
below, building on the framework proposed by
Rehfuess, Bruce & Bartram (2009):
• Sanitation sector coordination: contribute to the
coordination function led by a senior ministry, and
engage in intersectoral cooperation.
• Health in sanitation policies: ensuring health
considerations are rmly embedded in sanitation
policies, and that sanitation is embedded in relevant
health policies.
• Health protecting norms and standards: Advising
on setting norms, safety standards and sanitary
legislation; ensuring that the needs of women and
disadvantaged groups are accommodated in public
sphere sanitation facilities. This includes provision
for menstrual hygiene management and access for
people with impaired mobility.
• Health surveillance and response: Assessing
sanitation status and risks, linking with and
strengthening health surveillance systems, and
targeting interventions according to health data.
• Health programme delivery: ensuring sanitation
aspects as well as inspection of community level
sanitation conditions are embedded in relevant
health programmes; and leading control measures
in the event of enteric disease epidemics.
• Sanitation behaviour change: overseeing sanitation
and hygiene behaviour change interventions (see
Chapter 5) and liaising with other relevant health
departments and programmes for implementation.
• Healthcare facilities: setting standards and
monitoring systems for delivery of sanitation services
in healthcare settings for the benet of patients,
sta and carers and for protection of the health of
surrounding communities.
In addition to these core health functions,
environmental health departments are also
accountable for participating in cross-sectoral
sanitation planning. They are also responsible for
oversight, monitoring and enforcement of sanitation
safety standards in private, public and business
premises, in the environment, and in the provision
of sanitation services. Some of these functions are
discussed further below.
4.6.1 Oversight and enforcement
The objective of enforcement is to achieve the best
possible public health outcome. On this basis, it should
be seen as part of a larger spectrum of activities that
includes education and sanitation promotion, with
punishment of oenders as a last resort. It must be
feasible for people to adopt the desired behaviour
(e.g. building and using a toilet, connecting to a
sewer, using an improved emptying service, etc.), so
enforcement and promotion must be coordinated with
services development and information campaigns. In
practice, this means joint planning and coordinated
implementation by environmental health authorities,
service providers, local authorities and funders.
Oversight and enforcement is an ongoing task that
continues periodically after sanitation adoption and
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is used to check on sustained use and the integrity of
facilities and sanitation service chains.
Certain enabling conditions are required for
environmental health staff to undertake their
enforcement role including access to inspect the
public health conditions of facilities, information
management systems for collection, aggregation and
analysis of data, enforcement powers to follow up on
non-compliant facilities and services.
4.6.2 Monitoring
Monitoring is a key environmental health function to
track progress, and inform management decisions.
This is especially important given that safe sanitation
systems depend on continuously provided services
meeting the principles of safe management at each
step (Chapter 3).
Monitoring is required at various levels:
• Individual facility level: checking that sanitation
standards are being met and good hygiene
behaviours practiced;
• Community level: environmental health inspections
to check standards and practices are met in all
settings across the entire community;
• Utility or service provider level: ensuring sanitation
safety plans are present and implemented, and that
standards are met along the sanitation service chain
• Sub-national level: ensuring by-laws and
regulations are set and monitored; measuring
sanitation indicators and quantifying progress;
• National level: aggregating the local statistics to
national level to track progress towards national
and global targets;
• International level: monitoring progress towards
the SDGs.
The indicators used and information required for
these different levels of monitoring differ, with a
larger number of indicators needed at the individual
facility, utility and sub-national levels to inform local
programmes and actions, while a smaller number
of indicators are used for national and international
monitoring to track progress towards sector targets.
Information on the toilet end of the sanitation service
chain can only be obtained by visiting people where
they live. This is done systematically, but periodically,
in the national census and in some cases through
decentralised monitoring mechanisms. Household
surveys led by national statistical authorities, as well
as externally-supported surveys such as the multi-
indicator cluster survey (MICS) and the demographic
and health survey (DHS), typically undertaken every
four to ve years, are usually powered to provide
information for national and sometimes sub-
national level, but do not provide sucient detail for
comprehensive local planning. It is important that
environmental health sta be involved in training
enumerators for these surveys, so that the data
collected are accurate, consistent, meaningful and
linked to standards for targets. Developing a set of
support tools for surveyors, such as illustrations, to
show which technologies are classied as improved
or unimproved, or meeting other national denitions,
can improve consistency.
At the individual, utility or service provider and sub-
national monitoring level, environmental health ocers
may do some of the monitoring, and also support local
authorities and health workers in monitoring sanitation
and hygiene behaviours. Environmental health sta
should also monitor the containment, conveyance and
treatment and safe use/disposal steps. Where lapses are
observed, remedial action should be initiated with the
relevant person or institution.
Practical considerations dictate that only a limited
number of indicators can be monitored. In any given
situation, a risk assessment should highlight critical
control points that should be regularly monitored.
It is also important that at least the basic indicators
tracking the SDG target for sanitation (see Figure 4.5)
are monitored.
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CHAPTER 4. ENABLING SAFE SANITATION SERVICE DELIVERY
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SDG target 6.2 on sanitation is tracked at the global
level through the indicator of proportion of the
population using safely managed sanitation services,
which is dened as the population using an improved
sanitation facility that is not shared with other
households, and where excreta are either:
• treated and disposed of in-situ;
• stored temporarily and then emptied and
transported to treatment o-site; or
• transported through a sewer with wastewater and
then treated o-site.
Core indicators within national monitoring systems
should capture global monitoring elements as a
minimum as well as additional nationally relevant
elements of safe management (Chapter 3) and
implementation (Chapter 4) to monitor nationally
relevant service levels, settings, sub populations and
enabling environment.
To monitor sanitation, environmental health ocers
may play an important role in collecting individual
and sub-national level information on:
a) Sanitation and related facilities (superstructure,
handwashing facilities) and the way they are used.
b) For on-site facilities, the eectiveness and safety of
in-situ treatment or the emptying and transport of
faecal sludge.
c) For sewerage, the extent of leakage and overow
of untreated sewage.
d) The effectiveness of faecal sludge and sewage
treatment against national standards or permits.
e) The extent and effectiveness of community
engagement on sanitation.
Data on sanitation and handwashing facilities (a) and
the in-situ treatment for on-site facilities (b) should
be collected through the inspection of dwellings and
buildings (this may be done routinely, in periodic/
special surveys or in the national census). Data on
the emptying and transport component for on-site
facilities (b) and on leakage or overow of untreated
sewage (c) should be collected from customers,
formal and informal operators and, where relevant,
licensing authorities or regulatory bodies. When
information is collected by operators, it should be
Figure 4.5 The components of the SDG sanitation ladder (based on WHO and UNICEF, 2017)
SERVICE LEVEL DEFINITION
SAFELY MANAGED Use of improved facilities that are not shared with
other households and where excreta are safely
disposed of in situ or transported and treated o-site.
BASIC Use of improved facilities that are notshared
with other households.
LIMITED Use of improved facilities shared between two or
more households.
UNIMPROVED Use of pit latrines without a slab or platform ,
hanging latrines or bucket latrines.
OPEN DEFECATION Disposal of human faeces in elds, forests,
bushes, open bodies of water, beaches or other
spaces, or with solid waste.
SAFELY
MANAGED
SERVICE
EXCRETA
TREATED AND
DISPOSED
OF IN SITU
WASTEWATER
TREATED
OFFSITE
EXCRETA
EMPTIED AND
TREATED
OFFSITE
BASIC
SERVICE
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WHO GUIDELINES ON SANITATION AND HEALTH
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backed by periodic observation or audit to ensure
that information provided is correct. This component
should intentionally capture data on management
of full pits, including informal and manual emptying
practices. Data on the eectiveness of sludge and
sewage treatment (d) should be collected from
operators and veried by occasional sampling and
independent laboratory analysis. A good basic
principle to apply in service provider regulation
on (b), (c) and (d) is for them to report specified
monitoring information, subject to challenge
inspection by environmental health authorities.
The frequency of such inspections depends on the
level of trust by environmental health sta in the
service providers and the potential hazards arising
from non-compliance. Information on sanitation
community engagement (e) requires discussions
with local officials and community members. A
comprehensive set of sanitary inspection forms
has been developed to assist environmental health
ocers in this process (see WHO website: http://www.
who.int/water_sanitation_health/en/).
Taken together with information on open defecation
(collected through community monitoring data
or environmental health inspections), these data
enable the assessment of sanitation according to
and beyond the SDG denitions, as well as to inform
planning. Where non-specialist sta are involved in
data collection (e.g. in specic surveys or a census)
it is important that environmental health sta assist
with enumerator training, including some supervised
fieldwork, to ensure that the basic concepts are
understood and improve consistency.
Incentives to collect monitoring data, and the resources
required to do so, may be limited. As mentioned in
respect of accountability, the incentive may be that
such data are required to release certain government
budgets, especially where specific budget lines,
funding windows and expenditure codes for sanitation
at central and local government levels have been
established. Part of these budgets should be assigned
to cover the costs of monitoring.
4.6.3 Managing sanitation and hygiene
promotion
The consistent use of sanitation facilities and promotion
of improved hygiene behaviour is a fundamental and
essential component of sanitation intervention and is
outlined in 4.7.2 and detailed in Chapter 5. To enable
environmental health sta to play their role fully, they
should receive training to equip them to manage
specialists and contractors and to advocate internally
for the allocation of sucient resources for sanitation
behaviour change. It is also necessary to formally
train frontline sta, such as extension and community
outreach ocers.
4.6.4 Risk assessment
Environmental health sta should be involved with
the sanitation risk assessment process (4.4.2) and
monitor relevant health and epidemiological data
(such as that collected through routine surveillance
at health care facilities) to help to identify the public
health burden related to poor sanitation. They should
also check that women, girls and vulnerable groups
are adequately served. This may be partially possible
from the epidemiological data (depending upon its
quality) possibly combined with general observations
and focus group discussions. This vigilance needs
to extend beyond people’s immediate living and
working environments to wherever faecal material
is being used or discharged into the environment.
Based on this, they can identify high risk areas where
priority should be given to improving sanitation.
4.7 Delivering sanitation at local
level
4.7.1 Sanitation as a basic service
In all environments, maximum health benets can
only be obtained from sanitation when combined with
adequate water supply and good hygiene behaviours.
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In a high density (urban) environment sanitation is
closely linked to land-use patterns, housing occupancy
patterns, level of water supply services, drainage and
solid waste management and cannot be managed
independently of them. Planning and implementing
sanitation must therefore be coordinated with these
other basic services.
In practice, the only institution empowered to act in all
these areas is local government, so overall responsibility
for sanitation must be placed with them, even where
sanitation service provision has been delegated to a
utility company or is delivered by the private sector.
As noted earlier, sanitation must be identied explicitly
in the planning and budgeting process, which
should recognize nationally- and locally-established
service level targets. In order to align the activities
of the various sectors that contribute to sanitation,
a city or district level coordination group with senior
representation from all relevant departments, and
other key stakeholders, such as service providers and
user representatives, should meet periodically.
4.7.2 Sanitation behaviour change
Active user participation is needed to achieve
sanitation and good hygiene. Multiple behaviours
by dierent stakeholders require addressing along
the sanitation service chain, and may require specic
strategies. Chapter 5 examines sanitation behaviour
change in detail, using ending open defecation as
an example. Behaviour change should be seen as
an integral component of providing sanitation, as
concentrating on infrastructure and services alone will
not deliver the desired public health outcomes.
4.7.3 Local monitoring
Monitoring systems should be based on whatever
frontline sta are available in the communities to
increase sustainability and reduce costs. They might
be formal or informal community leaders, or sta
from health, agriculture or other sectors which
have a community presence. Budgets should be
programmed for the purpose, and a continuous
training programme established; the number
of people involved is large, so natural attrition
generates an ongoing training need, in addition to a
requirement for refresher training (see also Section
4.6.3). A database should ideally be maintained, with
georeferenced information on sanitation facilities
and their condition; this should assist in planning
and managing further sanitation interventions and
in providing information for the design of sanitation
promotion strategies (see Chapter 5).
4.8 Developing sanitation services
and business models
4.8.1 Designing services
Sanitation services must respond to the physical, social
and economic conditions prevailing in each area, and
these factors should be assessed prior to embarking
on sanitation improvements. Using the risk assessment
(Section 4.4.2) as a basis, inadequacies in the existing
sanitation situation can be identied, based on existing
documentation, local expert knowledge, dialogue
with users, a general survey of the area to identify
sanitation issues and, if possible, household surveys.
Further assessment, by examining legal and policy
documents and interviewing key stakeholders, should
be carried out to understand how the formal and
informal institutions and service providers, rules and
practices create this situation. The assessment process
should actively engage with the stakeholders and aim
to develop a common understanding of the situation.
It should be possible to identify if, and at what stages,
the sanitation service chains are failing, where these
failures pose the greatest risks to public health, and
the market supply, user demand, and institutional
factors that have led to this. In an iterative process
involving the stakeholders (especially users), possible
interventions should be formulated, and their viability
assessed, to arrive at feasible solutions that produce
the greatest impact on public health. The solutions
should address all aspects, including:
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• hardware;
• sanitation promotion and behaviour change;
• institutional development;
• legislation and regulation; and
• nancing.
Wherever possible, they should build on or make use
of existing capacity and infrastructure.
As outlined in Section 4.2, sanitation services may be
provided by the private sector (informal and formal),
utility companies (commercialized public entities),
local government or any of these in combination.
Services which provide direct benet to the user, such
as hardware supply, toilet construction or desludging,
can often function well as private businesses, provided
that they are regulated to ensure safely (Chapter 4.4)
and poorer households have access to subsidies to
ensure services are aordable. Faecal sludge treatment
and, particularly, sewerage systems require major
capital investment, which could be difficult for a
private company to nance, and so usually require
public investment. They may be managed directly
by the public sector or a utility company or leased to
a private operator. The leasing option is particularly
suited to faecal sludge treatment and incentivizes
resource recovery.
As cities grow, there is an increasing need for
decentralized sanitation systems in urban areas, both
small sewerage systems and faecal sludge transfer
facilities and treatment sites. These make good sense
in engineering terms but may be challenging to
implement due to diculties in acquiring land, or
in the face of resistance within the neighbourhood.
Land acquisition issues can be partly resolved by
adopting planning regulations – which may already
exist – that require land to be reserved for sanitation
infrastructure, and making allowances in urban
zoning and land-use plans.
Where there is local resistance, this can often be
overcome by working with communities to explore
options and incentives. A number of treatment
technologies (such as anaerobic baffled reactors
or upow anaerobic sludge blankets) are installed
underground, do not create smell, and can create a
hard, at surface that can be used as a community
space. Biogas generated by the process can be given
to nearby residents, and other incentives can be
negotiated if necessary. In the case of transfer facilities
for faecal sludge, mobile units can be used if local
resistance to a permanent structure is too strong.
4.8.2 Sanitation service capacity building
Adopting a systematic and inclusive approach
to sanitation is likely to create a need for formal
services that do not currently exist (or only on a
small scale). These services and their support
requirements are diverse in their nature, ranging
from hardware manufacture and provision to faecal
sludge management. Some common factors are
outlined below.
A new type of service requires technical development.
Partnerships with academic institutions, NGOs or social
enterprises can support both initial development
and ongoing adaptation of the service. For a more
mature service a franchise model can be considered.
In this case the franchisor provides training, technical
backstopping, quality control, marketing and, possibly,
certain specialized equipment to franchisees. In all
cases, the partnerships should include people with
environmental health knowledge to oversee risk
assessment, system improvements and operational
monitoring as well as supporting programmes such as
training to ensure that the systems developed deliver
safe sanitation.
Associations of service providers can be very useful
and should be promoted where they do not exist. They
facilitate the dialogue between the service providers
and the authorities responsible for sanitation, and
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can be the entry point for training and certication.
Associations can play a useful role in informing
nancial institutions about sanitation businesses (with
which they are probably unfamiliar) and help develop
lines of credit.
Training is a crucial component of capacity building
and peer-to-peer learning and on-the-job mentoring
can be particularly eective. Service providers should
receive training in business as well as technical skills
to promote eciency, minimize costs and, ultimately,
improve sustainability.
Small enterprises may need assistance in obtaining
equipment and working capital to make a start.
Possible mechanisms include:
• Joint representation to nancial institutions to
facilitate access to credit.
• Small grants or equity contributions from government
or project funds.
• Leasing of equipment.
• A guarantee fund, to facilitate borrowing.
• Results-based nancing agreements, often used
with repayable nance to provide comfort to the
lender.
• Advance purchase agreements – guaranteeing a
market to a specied level.
Demand should be activated and sustained, once
services are operational, with ongoing marketing and
informational campaigns and judicious enforcement
of public health regulations. Where there are multiple
small service providers, a common brand and
marketing campaign enables the use of mass media,
which may only be aordable on a collective basis.
4.8.3 Working with existing sanitation service
providers
In urban areas, improved sanitation usually competes
with traditional unsafe sanitation services. Traditional
service providers should be persuaded and encouraged
to work with the new, improved services to make use
of their acquired knowledge on wastewater and faecal
sludge and people’s behaviour regarding toilets. This
takes them out of the market for unsafe services and
discourages them from sabotaging the improved
services to protect their livelihoods.
Some of the traditional service providers may be socially
marginalized and unwilling or unable to participate in
a formalised, regulated service. Encouraging licensed
service providers to employ them can reduce this,
provided they can conform to acceptable standards
of behaviour and safety. It is important to engage with
them at an early stage to make them into part of the
solution instead of part of the problem. Irrespective of
how these workers are incorporated into the improved
sanitation system it may be necessary to take specic
measures to eradicate any residual bad practice once
a market providing a sucient volume of alternative
and safe services has been established.
4.8.4 Financing services
People are prepared to pay (at least partially) for
sanitation services at the toilet, containment and
on-site treatment, and parts of conveyance (see
Chapter 3) that benet them directly. Other aspects
of conveyance, treatment and disposal or use are
shared and perceived as services that benet entire
communities, which may require public or joint
nancing strategies such as taris and taxes. Tari
structures should reect the ability to pay for services
to prevent exclusion of poor households from services.
In urban areas, sanitation fees can be combined
within the water tariff, especially if all sanitation
services (sewerage and non-sewered services) are
managed by a utility. They can also be included in
local taxes, although it can be harder to ensure that
the funds raised through this mechanism are directed
towards sanitation.
In low-density rural areas, where the principal activity
is sanitation promotion and the safe and consistent
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use of self-built toilets, there is little alternative to
that of using government budgets for these activities.
A particular issue arises where toilets need to be
emptied, as the extra cost of improving toilets to
enable mechanical as opposed to manual emptying
also benets residents in the surrounding area (by
avoiding local dumping of the faecal sludge). A similar
issue arises if sewerage systems are extended into
low-income areas where residents may be unable to
meet the cost of the internal plumbing required. In
these circumstances it may be justied to partially
subsidize the cost to the user from the same sources as
used for the other publicly shared costs of sanitation.
It should also be noted that large-scale purchase
and construction of prefabricated toilets may be
able to bring the price down substantially in such
programmes.
In very poor communities, or for vulnerable
households, even a basic toilet may be unaordable,
and specially targeted subsidization may be needed.
Possible mechanisms for owner-occupiers, in low-
income urban areas include social security safety
nets or community-administered funds. Low-income
landlords should access these social security safety
nets or community-administered funds for the benet
of their tenants. However, there is a risk that this may
result in increased rent and the possible displacement
of the poorest tenants to inferior accommodation. An
alternative for those living in rented accommodation,
especially in high density areas without secure tenure,
is container-based sanitation, since it can oer a direct
service to tenants without them bearing the full cost
of investment in improving a home they do not own.
In low-density rural areas where it is assumed that
only very limited cash costs will be incurred for toilet
construction, community labour could be used.
Services such as desludging may be too expensive
for some customers and will, in many cases, have to
compete with manual desludging, which usually has
a lower cost as it does not include safe transport and
safe disposal. This may be countered by smoothing
payments through a regular aordable tari. It may
also be necessary to subsidize these services, possibly
through a voucher or other output-based system.
Demand for desludging services is often seasonal,
which can be problematic for a small business. This
can be partly offset by taking on other business
activities, such as solid waste collection, which can
oer a steady income throughout the year, or setting
up a scheduled emptying program to implement
preemptive rather than reactive emptying and spread
demand across the year.
The processing of faecal sludge and sewage into
products for sale (e.g. biogas, solid fuel or compost
or irrigation water for agricultural use) can help oset
some of the costs of treatment, although it rarely covers
the full cost (Otoo & Drechsel, 2018). When considering
product options, it is important to assess the market for
a proposed product to see if the required quantities,
quality and delivered costs match the production
potential. Environmental legislation to encourage their
use, can make such products more attractive than they
might otherwise be. The public health implications of
the diverse types of end use should always be assessed
when deciding on what products to make and the costs
of ensuring product safety should be reected in the
nal cost. Once an option is chosen and implemented,
appropriate control measures and monitoring regimes
should be formulated to ensure ongoing safety in the
use of the products (WHO, 2006; WHO, 2016).
4.9 Fostering the sanitation services
market
A sustained promotion programme is necessary to
foster new norms of sanitation behaviour. Marketing
and promotion of behaviour change requires
substantial resources to produce results. The desired
behaviour changes (e.g. Section 4.7.2) and messages
should be clearly dened, and interventions should
be based on adequate research among the target
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groups, combined with inputs from experienced
professionals as detailed in Chapter 5.
Several types of sanitation services are likely to be
supplied by commercial or partly-commercial entities:
• hardware supply and construction of toilets;
• pay-per-use public toilets; and
• desludging or container exchange.
In all cases, lowering prices through competition is
good for both customers and providers because it
makes the market more accessible to users, while also
increasing sales volumes.
In the case of hardware and toilet construction, the
rst step is to develop combined toilet-containment
system products appropriate to the target market
– they should meet aspirations, t comfortably into
the type of housing to which they are targeted, be
aordable and t with the rest of the sanitation service
chain. Bundling such products with consumer credit
(from suppliers and/or micro-nance institutions)
and installation in a package can be very eective.
Direct marketing sales and marketing efforts for
the products or package are essential and a shared
branded marketing campaign may be eective.
In the desludging market, the widespread presence
of mobile phones in urban areas has allowed, in some
cases, the development and use of call centres or
automatic digital platforms where customers can nd
service providers, and where the service providers
can compete on price (Aquaconsult, 2018). Creating
such an ecient market is likely to be more viable
than trying to control prices through regulation, as it
can balance willingness to pay against service costs.
There is also potential for quality control by gathering
customer feedback. Where a database of toilets
has been developed, this type of platform can also
become a good source of monitoring and planning
data. Geo-location chips can be tted to licensed
desludgers’ equipment to enrich the database.
Container-based sanitation services are under
development. Costs depend strongly on the scale of
the service and the density of customers (proportion
of all households in a local service area using the
service). Marketing is, therefore, crucial to delivering
an aordable container-based service.
Although some services require subsidy for the poorest
households, managing large one-time payments
such as sewerage connection or desludging fees
by incorporating them into a regular monthly tari
can make them much more aordable, especially to
poorer customers. A database of non-sewered toilets
is a necessary component of any schemes including
regular scheduled desludging. It is appropriate
to mobilize frontline workers and local leaders to
undertake the necessary periodic eldwork as this is
useful to the authority responsible for sanitation.
4.10 Management of special
sanitation risks
4.10.1 Sanitation in emergencies
Other publications (e.g. the Sphere handbook, 2018)
provide specialized guidance on sanitation in disaster
situations. These guidelines focus on including
sanitation in disaster preparedness planning as an
immediate priority action. To facilitate this, sanitation
and hygiene materials should be purchased and pre-
positioned along with other emergency supplies
(such as those for shelter, nutrition and health). These
emergency supplies include:
• picks and shovels for digging pit or trench latrines;
• latrine slabs or container-based sanitation
cartridges;
• material for superstructures – with full provision
for privacy and lockable doors;
• appropriate anal cleansing materials or containers;
• jerry cans and handwashing stations;
• soap; and
• lime for use in faecal pollution incidents.
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If a refugee or internally displaced persons (IDP) camp
is established, it is important to ensure that, as far as
possible, it is situated in an area where latrines can
be dug (i.e. not in areas of high water table or rock).
Often camps are sited on marginal land which may
be more easily available than land with soil cover
and a reasonably low water table, but this presents
major problems and risks with regard to sanitation.
As camps often eectively end up becoming urban
settlements, full service chain sanitation with
sewerage or faecal sludge management and eective
treatment should be considered once the immediate
disaster phase is over, as the densities are too high to
support ll-and-cover pit latrines over a long period.
Consideration should also be given to situations in
which camps are not provided or emerge informally,
including assessment of the impact of refugee or IDP
inuxes on the refugees and IDPs themselves as well
as host communities.
Container-based systems can also be used in
emergency situations and can be deployed very
quickly and can also provide a long-term service.
Shared toilets that substitute latrine pits with plastic
tanks, which can be replaced periodically and trucked
away for o-site treatment, do not need dry organic
waste and can provide an eective interim service.
Recommendations on other incremental control
measures can be found in Chapter 3.
Provision for people with disabilities, for children, and
for women’s privacy, safety and menstrual hygiene
needs are critical and need careful planning during
emergencies, when women and girls are especially
vulnerable.
4.10.2 Sanitation during enteric disease
outbreaks and epidemics
Special attention should be paid to sanitation during
disease outbreaks and epidemics of enteric diseases
with a faecal-oral transmission route including cholera
etc. Preventive action to reduce faecal load in the
environment (see Chapter 3) especially in known
hotspots with recurrent outbreaks, is more eective than
attempts to disinfect faecal material in the environment.
Disinfection of faeces is usually futile because organic
material in faeces has a very high chlorine demand, it is
also time-consuming and expensive.
A rapid sanitation safety planning approach can be
applied to identify risks, prioritize action and monitor
key actions. While the specic characteristics of each
situation are dierent, the highest-priority actions
should be focused on where exposure to sanitation
hazards is likely to be highest and cause the greatest
risk, such as the toilet and containment part of the
service chain near where people live and work. Some
measures – typically related to hygienic practices
and minor repair and maintenance activities – can
be taken immediately, while others requiring more
complex interventions may require weeks or months.
Some of the immediate and longer-term measures
that may be considered at various stages of the
sanitation service chain are set out in Box 4.2.
It should be remembered that a major causative
factor in enteric disease epidemics is poor sanitation.
Such events can be used to sensitize decision-makers
to the importance of improving sanitation, and it is
important to follow up with longer-term measures to
prevent a reoccurrence.
4.10.3 Sanitation in health care facilities
Heath care facilities represent a particularly high
sanitation risk, due to both infectious agents and
toxic chemicals. From the user perspective they
should be a model of hygienic sanitation. Health care
facility sanitation should be under the responsibility
of the Ministry of Health, with responsibility for its
management clearly specied in the job descriptions
of health care facility managers and relevant sta.
Recommended numbers of toilets are 1:20 for
inpatients and at least two toilets for outpatient
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Box 4.2 Immediate preventive measures for areas at high risk of enteric disease outbreaks
Neighbourhood and household level
Immediate measures
Undertake neighbourhood and house-to-house sanitary inspections to identify open defecation sites and leaking or overowing sewer connections,
open drains and pits or tanks of on-site sanitation facilities.
• Where open defecation is prevalent, undertake demand creation and sanitation promotion (see Chapter 5), using properly trained sta if
available, with the objective of persuading open defecators to use an existing neighbour’s or community toilet, where available.
• In urban areas, using a combination of sanitation promotion/behaviour change strategies and enforcement, persuade owners to empty
overowing but otherwise serviceable permanent sanitation facilities where this is a viable option.
• Carry out intensive hygiene promotion, focusing on: immediate care-seeking; handwashing with soap; prompt disposal of child and infant
faeces in a safe toilet; hygienic practices in the care of sick individuals and management of their faeces; hygienic practices in the washing and
burial of corpses; avoiding contact with water in drains (especially children); and treatment of drinking-water supplies.
Promote and support the installation of handwashing facilities in homes and institutions.
Medium term measures
• Using a combination of demand creation and enforcement, persuade owners to x leakages and rebuild or upgrade unsafe toilets, or to build
a toilet where there is none.
• Where it is not possible to substitute open defecation with individual household toilets, organize the construction of community toilets shared
between limited and dened groups of households, with robust operation and maintenance arrangements.
• Where liquid euent from on-site sanitation facilities is discharged into drains and waterways, or where there are leaking sewer connections,
promote the construction of soakaways and drainelds where feasible. Where this is not feasible, organize mass desludging to increase euent
residence times in the tanks and decrease solids carry-over.
At health posts, hospitals or emergency facilities for infected people
Immediate measures
• Eliminate leakages and overows of liquid euents urgently, and carry out all feasible minor repairs and desludging to maximize the eciency
of the existing sanitation system.
• Ensure sanitation facilities are operational, accessible to all, and have handwashing facilities with soap and water nearby.
Medium term measures
• Review sanitation arrangements, to ensure that all faecal material is contained and that all liquid euents are treated on-site and inltrated
to soil though a leach eld or discharged to a sewer and treated and safely disposed (see sewerage and wastewater treatment below).
Faecal sludge management
Immediate measures
• Disseminate messages to promote the use of licensed desludging operators (where applicable).
• If it will result in less open dumping, temporarily suspend the charging of tipping fees.
• Urgently inspect all faecal sludge management equipment and oblige operators to rectify any faults that could result in inadequate containment
or spillage.
• Increase vigilance against open dumping of faecal sludge and institute strong measures to ensure that operators discharge at authorized sites.
• Promote, and enforce with follow up inspections, the use of disinfectants to clean up premises which have been serviced, and the desludging
equipment used.
Medium term measures
• Review operating practices with all desludging operators to minimize risks for both operators and customers.
• Contact the traditional emptiers and enlist their cooperation to the extent possible, promoting the burial of faecal sludge over dumping
it in drains, water bodies or open land.
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settings (one toilet dedicated for staff and one
gender-neutral toilet for patients that has menstrual
hygiene facilities and is accessible for people
with limited mobility) (WHO, 2008). They should
be culturally acceptable, private, safe, clean and
accessible to all users, including provision for those
with reduced mobility and for menstrual hygiene
management. Bedpans should be used by patients
only when needed, and not as a regular substitute for
toilets; when used, bedpans should be safely handled
avoiding spillage and using appropriate PPE. Faecal
waste from bedpans and water used for washing
bedpans should be emptied into a toilet or into the
sanitation system through other means such as a
sluice or macerator. A reliable water point with soap
should be available close to toilets for handwashing.
All faecal waste (including from bed pans) and
greywater should be fully contained. If a sewer
connected to a fully functional treatment plant is
available, these wastes can be combined and
discharged to it. If no sewer is available, the faecal waste
and greywater should be conveyed in separate drains.
The faecal waste should be treated in an appropriately
sized treatment facility, with the greywater being
added at the secondary stage. The liquid effluent
should be contained on-site, by way of subsurface
inltration. If that is not possible, the liquid euent
should be disinfected in a baffled tank providing
adequate contact time, before discharge into the
environment beyond the health care facility. The liquid
euent should never be used, even if disinfected.
A budget for operation and maintenance of the
health care facility wastewater system must be
consistently allocated. An adequately trained
staff member should have officially designated
responsibility for the system, with sta allocated to
maintenance tasks. Management of the wastewater
system should be on the standing agenda of the
group in charge of infection prevention and control,
as should the management of laboratory wastes,
solid waste management and the safe treatment of
infectious waste.
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References
Aguaconsult (2018) Engaging with the Private Sector for Urban
On-site Sanitation Services: Lessons from six sub-Saharan African
cities, Bill & Melinda Gates Foundation.
De Albuquerque C (2014). Realising the human rights to water
and sanitation: a handbook. Oce of the UN Special Rapporteur
on the Human Right to Water and Sanitation, Portugal: UN
Habitat.
Mills F, Willetts J, Petterson S, Mitchell C, Norman G (2008).
Faecal Pathogen Flows and Their Public Health Risks in Urban
Environments: A Proposed Approach to Inform Sanitation
Planning. Int J Environ Res Public Health. 23; 15(2).
Otoo M, Drechsel P (Eds.) (2018) Resource recovery from
waste:business models for energy, nutrient and water reuse
in low- and middle-income countries. Oxon, UK: Routledge -
Earthscan. 816p.
The Sphere Project (2018). Humanitarian charter and minimum
standards in humanitarian response.
Therkildsen, O. (1988) Watering White Elephants? Lessons from
Donor Funded Planning and Implementation of Water Supplies
in Tanzania. Uppsala: Scandinavian Institute of African Studies.
World Health Organization (2006). WHO guidelines for the
safe use of wastewater, excreta and greywater. WHO, Geneva,
Switzerland.
World Health Organization (2008) Essential environmental health
standards in health care. World Health Organization, Geneva,
Switzerland.
World Health Organization (2016) Sanitation safety planning:
manual for safe use and disposal of wastewater, greywater and
excreta. World Health Organization, Geneva, Switzerland.
World Health Organization and UNICEF (2017). Progress on
drinking water, sanitation and hygiene: 2017 update and SDG
baselines. WHO and UNICEF, Geneva, Switzerland.
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Chapter 5
5.1 Introduction
Like many public health programmes, sanitation
programmes have historically tried to influence
practices through the direct provision of hardware (e.g.
by constructing toilets, sewage networks and treatment
plants) and with various forms of health education or
health promotion. Lessons from practice and behavioural
science studies, however, have shown that people choose
to use toilets and practice related hygienic behaviours for
many reasons other than the desire to improve health
(Jenkins & Curtis, 2005; Curtis, Danquah & Aunger, 2009).
Behaviour change is now seen as an essential component
of sanitation programmes, whether to improve the
uptake of sanitation solutions, hygienic practices in
households or, indeed, in the institutions responsible for
sanitation programming.
Behaviour change among a range of stakeholders
is necessary for sanitation interventions to improve
public health. Chapters 3 and 4 cover various
important behaviours relating to the delivery and
management of sanitation services. This chapter
focuses on fostering behaviour change at the
individual, household and community-level, through
behaviour change interventions designed to increase
the adoption of household toilets and their consistent
use, management and maintenance.
Depending on the specic situation, desired user
behaviours may include:
• Abandoning open defecation and adopting safe
sanitation facilities.
• Handwashing with soap at critical times.
• Building and using non-emptiable pit latrines,
which are covered over when full and new facilities
constructed.
• Building and using permanent on-site facilities
with access for emptying and accessibly situated
for emptying equipment.
• Ensuring the regular desludging of such facilities
and the inltration of liquid euents to the subsoil
or other safe disposal route.
• Connecting to a sewerage system where available,
and paying the service charges.
• Safe practices in handling wastewater and faecal
sludge in food production and sale.
5.2 Institutional and government
responsibilities for sanitation
behaviour change
Governments are the critical stakeholder in the
coordination and integration of behaviour change
initiatives at the local level and should provide
leadership and ensure funding. The point is made in
Chapter 4 that sanitation behaviour change requires
nancial and human resources, and that failure to
commit sucient resources may lead to failure to
achieve sustained adoption or use of household
sanitation services.
Health authorities should ensure that all sanitation
interventions include a robust sanitation behaviour
change strategy. This applies whether there is a
national effort to improve sanitation in general,
Chapter 5
SANITATION BEHAVIOUR
CHANGE
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or when sanitation is included as part of a disease
control programme (e.g. as part of environmental
improvements for trachoma elimination, in
prevention of and response to cholera outbreaks,
in nutrition programmes or for reducing intestinal
worm infections in children). Sufficient staff with
specialized expertise and nancial resources must
be allocated to sanitation behaviour change and
work should be conducted in coordination with
those providing infrastructure and services in order
to ensure that demand is not created for non-existent
services or that services are oered but not purchase,
or provided but not used.
While many health authorities have departments
dedicated to developing health promotion
interventions, where such departments do not exist
or lack the necessary skills and resources to design
evidence-based behaviour change programming,
health authorities should nonetheless be able
to provide oversight and direction to programme
design. This may involve engaging with organizations
with technical and subject matter expertise, such as
universities and social marketing and design agencies.
At a minimum, health authorities should:
• Provide oversight on suitable approaches and their
implementation and monitoring.
• Ensure that sanitation behaviour change eorts
are targeted, as far as possible evidence-based,
and that there is a solid monitoring and feedback
mechanism for learning and adaptation.
• Ensure that all actors are aligned around the same
set of behavioural objectives and strategies, so that
diverse eorts reinforce, rather than compete with,
or undermine, each other.
The Ministry of Health may be involved in the
formulation of sanitation behaviour change strategies,
in the setting of targets, and in the development
of local guidelines. While they may not be involved
in the direct management of sanitation behaviour
change interventions, they do have a mandate to
manage, coordinate and oversee the eorts of other
players, including external support agencies and
NGOs. The Ministry of Health is also the focal point for
knowledge management related to sanitation and
sanitation-related behaviours in their country. Accurate
and up to date information on current sanitation
practices (both nationally and within specic regions
or sub-populations) should be maintained. Nationally
representative surveys, such as the Demographic and
Health Surveys (DHS) and the Multiple Indicator Cluster
Surveys (MICS), are commonly used to create these
national and sub-national estimates on sanitation
coverage and use. Academic studies of sanitation
related behaviour may also be available. Data collection
on community-level sanitation status should also
be integrated into routine (e.g. health management
information system (HMIS)) or programme-specic
data collection activities. The Ministry of Health may
also provide technical support related to standard
indicators and methods for measuring behavioural
outcomes to ensure that sanitation-specic data is
shared between organizations and data collection
activities is comparable.
If the Ministry of Health fulls these roles it allows
other institutions to play their proper roles, which
include building capacity in local and regional
authorities, providing tools and technical support
for local programming and in relationships between
stakeholders.
5.3 Sanitation behaviours and
determinants
To design successful activities to inuence sanitation
behaviours it is important to understand the range of
existing sanitation behaviours and their determinants.
From a behaviour change perspective, sanitation
and hygiene present several distinct challenges. For
example, sanitation and hygiene behaviours may be
entrenched within long-standing daily routines–
behaviours done in a specific sequence within a
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specic environment at specic times of the day.
Sanitation behaviours may also require an expensive
physical modication to a home, namely the building
of a household toilet facility.
For sanitation to be eective (i.e. to ensure that people
do not have contact with pathogens in human waste
and that the pathogens are safely removed from the
environment), a variety of inter-related behaviours
are important. These include the sustained use of
facilities and their maintenance and upkeep, good
hand hygiene and the hygienic disposal of child and
infant faeces. Having access to a toilet is essential for
use to take place, but it does not guarantee consistent
use (Garn et al., 2017). There are multiple reasons why
existing facilities may not be used, including:
• Facilities may not be adequately accessible to
intended users, particularly women, older people
or people with disabilities.
• Facilities may not oer sucient privacy to users
given the intimate and often taboo nature of
sanitation behaviours (Sahoo et al., 2015).
• Facilities and the use of facilities may not provide a
safe environment free from harassment, violence,
or other physical and emotional forms of harm
(Kulkarni, O’Reilly & Bhat, 2017).
• They may be broken, dirty or uncomfortable to use.
• Individuals may prefer open defecation, particularly
when sanitation options are unappealing or
unhygienically maintained (Dreibelbis et al., 2015).
• Facilities may not be available at the times users
need them, such as when individuals are away from
home (school, work place, public places) or may be
locked at night (Caruso et al., 2017a, b).
• Users may be concerned about the impact of long-
term use on pit-lling and future maintenance,
thus avoid using the facility (Coey et al., 2014).
• Sharing facilities may discourage people from
using facilities, even when sharing is limited to
members of the same family (Coey et al., 2014).
• Shared and public facilities may be located at a
long distance; queues may also discourage use
(Kulkarni, O’Reilly & Bhat, 2017)
The determinants of behaviours of interest may be
positive (meaning that they promote the behavioural
outcome) or negative (where they act as a barrier to
the behavioural outcome). Behavioural determinants
are found at dierent levels (e.g. society, community,
individual, etc.) and include factors which can be
characterized as being related to context, technology
and psychosocial experiences (Dreibelbis et al., 2013).
For example, individual-level determinants of behaviour
include knowledge around toilet construction and use,
costs and benets, motivation and desire for sanitation,
and the way in which the behaviour ts in with daily
routines and habits.
Determinants that operate at the household level
could include roles and responsibilities and the division
of labour within the household.
At the community-level, determinants include societal
norms of toilet use and capacity for the management
and maintenance of facilities.
Behavioural determinants are related to the context in
which behaviours occur. These include determinants in
the physical environment such as climate, geography
and access to materials, economic determinants such
as access to goods and services, and institutional
determinants such as the availability of subsidies or
the enforcement of nes and/or penalties. Sanitation
technologies can also determine behaviour through,
for example, ease of use, location and cost.
The relationships between behavioural determinants
and behaviours can be complex and multiple
determinants often interact to inuence one behaviour,
as illustrated for open defecation in Figure 5.1.
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5.4 Changing behaviours
5.4.1 Main approaches
This section describes the dierent behaviour change
approaches commonly used for sanitation and
hygiene behaviour change. While myriad strategies
have been used, these typically fall into one or more
of four major categories (adapted from De Buck et
al., 2017):
• information, education and communication-based
(IEC) messaging approaches;
• community-based approaches;
• social and commercial-marketing approaches; and
• approaches based on psychological and social
theories.
Behaviour change programs often utilize more than
one approach.
Information, education and communication
approaches (IEC)
Messaging and awareness raising are the cornerstone
of conventional information, education and
communication (IEC) initiatives. IEC approaches
are often used in public health behaviour change
communication. IEC can include mass media, group
or interpersonal communication and participatory
activities. Specic approaches such as Participatory
Hygiene and Sanitation Transformation (PHAST) and
Child Hygiene and Sanitation Training (CHAST) use
IEC methods, are based on individual behaviour
Figure 5.1 Example of behavioural determinants for open defecation
Box 5.1 Sanitation behaviour change considerations for urban settings
The determinants of behaviour are likely to dier between settings and for dierent population groups. While there is often a strong focus within
sanitation behaviour change approaches on rural contexts, urban populations present distinct challenges and opportunities. Higher population
densities, higher rates of renting (compared to owning), lack of space, and a need for more complex sanitation service chains and or technologies
that serve more than one household may limit the opportunity for urban populations to improve their own sanitation services in the way that
is expected of rural populations (e.g. through the constriction of simple pit latrines). Social networks in urban areas can be less formal, so social
pressures and norms in urban areas may dier from those in rural areas, potentially reducing the eectiveness of interventions that rely on social
pressure for stopping open defecation. Violence and physical harm, specically against women and girls, related to the reliance on shared open
defecation spaces or public toilets, is increasingly reported in urban settings, necessitating strategies for improving sanitation that are responsive
to these needs. Urban populations typically have better access to cash resources, sanitation markets and technical support than rural populations.
Other populations with specic sanitation needs may include those in rented accommodation, those without land tenure, the homeless and
populations that are marginalized either socially (such as by class, caste, social status, ethnic or cultural identity) or geographically (O’Reilly,
Dhanju & Goel, 2017).
POSSIBLE DETERMINANT
OUTCOME
OPEN
DEFECATION
Lack of facilities
Poor quality/ foul-smelling/dirty facilities
Convenience
Habits
Lack of familiarity with toilets
Limited awareness of health consequences
Lack of anal cleansing materials
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change and do not explicitly target changing
collective behaviours.
IEC approaches often default to health messaging,
particularly around the health risk for children. Often,
however, populations are already aware of both the
risk of diarrhoeal disease and its prevention (Biran
et al., 2009; Curtis, Danquah & Aunger, 2009; Aunger
et al., 2010; Brewis et al., 2013), and health-focused
messaging fails to result in significant changes in
sanitation or hygiene behaviours (Biran et al., 2009).
Consequently, IEC is rarely used as a standalone
approach.
Community-based approaches
The focus of community-based approaches to
sanitation is the collective mobilization of groups
of people. Collective processes are used to develop
a shared understanding of a local problem, reach a
collective agreement on actions and to create new
norms around a specic behaviour. These norms help
to create new social pressures to comply with the
promoted behaviour.
There are multiple variants of community-based
approaches that have been applied to sanitation
programmes. Community-Led Total Sanitation
(CLTS) initiatives are the most widely known and are
directed at ending open defecation. CLTS is organized
around a “triggering event”; a series of community-
based activities, led by trained facilitators, which
focus on behaviour change and aim to ignite a sense
of disgust and shame in a community related to
open defecation and its impact on the community’s
health and well-being (Kar & Chambers, 2008).
Communities are facilitated to conduct their own
appraisal and analysis of open defecation and
take their own action to become open defecation
free (and although traditionally the CLTS method
stipulated that this should be free from subsidies
and other nancial inputs, this is no longer the case).
Communities are also facilitated to develop their own
approaches to maintaining and improving facility use.
CLTS programmes have been implemented in over
60 countries and have evolved in multiple ways to
improve outcomes on sustained sanitation use (Cavill
et al., 2015; Bongartz et al., 2016), including:
• targeting subsidies to marginalized households
(Robinson & Gnilo, 2016; Myers & Gnilo, 2017);
• tailoring initiatives to focus on the inclusion of
marginalized groups and households; (Wilbur &
Danquah, 2015; Bardosh, 2015; House et al., 2017;
Cronin et al., 2017);
• paying increased attention to supply-side
interventions such as social and commercial-
marketing based approaches discussed below, in
order to stimulate progress from basic to safely
managed sanitation (Thomas, 2014; Cole, 2015); and
• understanding reasons for slippage and reversion
to open defecation (Odagiri et al., 2017; Mosler et
al., 2018).
Community Health Clubs (CHCs) are another example
of a collective mobilization approach (Waterkeyn &
Cairncross, 2005). CHCs involve long-term engagement
with target communities, through weekly meetings
each addressing a specic health, hygiene or sanitation
behaviour. CHCs focus on making changes with local
resources and local innovation, and group activities
help to establish new positive norms around improved
hygiene and sanitation behaviours.
Community-based approaches are thought to be
more eective in rural communities with higher social
cohesion and where adoption of simpler technologies
is feasible, although specic data on the eects of
these approaches on sanitation adoption are scarce.
Social and commercial-marketing based approaches
Social marketing refers to the broad set of initiatives
that use commercial-marketing principles to change
health behaviours. Social marketing assumes that
sucient promotion and demand creation, when
met with accessible goods and services that meet a
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population’s needs at an aordable price, results in
changes in behaviour (Barrington et al., 2017). These
are reected in the “4Ps” of social marketing: product,
price, place and promotion.
Commercial-marketing approaches recognize that
most toilets are obtained by householders from local
markets and so focus on market development, at the
same time as developing and activating demand
for sanitation products and services. Market based
approaches in India, Cambodia and Vietnam have
resulted in the purchase and construction of 10s to
100s of thousands of toilets (Rosenboom et al., 2011),
while new technological approaches, for example
container-based sanitation toilets in urban Ghana,
Kenya and Haiti, have shown promise but have not yet
gone to scale (Greenland et al., 2016b). Developing
viable business models for sanitation providers
offering novel products or services has proven
challenging, marketing eorts have not always been
optimal and there is, to date, limited evidence of
effectiveness of the impact of commercial-based
approaches (De Buck et al., 2017). Few market-based
sanitation initiatives have achieved scale, and many
have required substantial and likely unsustainable
heavy subsidies and other external support to
remain viable (USAID, 2018). Commercial-marketing
approaches (likely) need to be accompanied by
targeted subsidies to reach the poorest (to improve
access to sanitation as well as to improve business
viability through increased reach), as well as demand
activation to ensure interest in toilet purchase results
in toilet purchase (USAID, 2018).
Approaches incorporating psychological and social
theories of behaviour
In recent years, models and frameworks drawing
on psychological and social theories (sometimes
alongside conventional approaches such as economic
utility theory), have been developed and applied to
sanitation and hygiene promotion and behaviour
change (e.g. Devine, 2009; Michie, van Stralen
& West, 2011; Mosler, 2012; Dreibelbis et al., 2013;
Aunger & Curtis, 2016). Given the relatively recent
development of these approaches for sanitation
and hygiene behaviour change, evidence for their
ecacy is primarily found from the application of the
underlying theoretical principles to other health and
development challenges. Approaches include the
use of environmental “nudges” to create or sustain
new default behavioural patterns and cue desired
behaviour (Dreibelbis et al., 2016), and strategies that
focus explicitly on habit formation through repetition,
fostering stable environments and reducing perceived
barriers to a behaviour (Neal et al., 2016). It is currently
not known whether the small pilot successes reported
thus far are context and behaviour specic or scalable.
Approaches based on psychological and social theory
are often associated with specic behaviour change
techniques (BCTs). These are the smallest building
blocks of a behaviour change intervention and refer
to the mechanisms through which intervention
or programme activities influence behavioural
determinants to result in changes in behaviour. A
taxonomy of BCTs (Michie et al., 2013) identied 93
BCTs organized within 16 broad categories. These
include categories such as schedule consequences
(negative reinforcement, punishment etc.), goal
setting (behaviour contract, action planning,
commitment) and social support. Most theory-driven
sanitation interventions use a range of BCTs, many of
which may not be psychosocial. Evidence suggests
that the use of multiple BCTs is more eective than
interventions that utilize a single or limited number
of techniques (Briscoe & Aboud, 2012).
Application of approaches to sanitation behaviour
change
The four categories of approaches described are
intended to provide a broad typology of potential
strategies, which are not mutually exclusive. Each
approach has its own strengths and weaknesses and
may be more or less applicable depending upon the
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Table 5.1 Summary of approaches and factors for consideration in their implementation
Approach Considerations for implementation
Health-driven approaches (Participatory Hygiene and Sanitation Transformation (PHAST), Child Hygiene and Sanitation Training (CHAST))
(PHAST, CHAST, IEC) • Health risks: Exclusive focus on the risks to health of poor sanitation practices has not proved to be a
powerful motivator of sanitation behaviour change because educational approaches that rely on health
messaging to increase knowledge and stimulate behaviour change do not address critical underlying
motives and social norms needed for behaviour change.
• CHAST: Assumptions that children will act as change agents to improve sanitation within their
household may not hold. Parallel community level approaches are needed.
• Health knowledge is a useful basis for behaviour change but needs to be combined with other
approaches to result in sustained behaviour change.
Community-based approaches (Community-led/ School-led Total Sanitation (CLTS/SLTS), Community Health Clubs (CHCs)
General to all community-based
approaches
• Facilitation: A network of well-trained, high-quality facilitators is essential for implementation at scale
• Community context: These approaches more applicable in rural settings where legal and physical
factors, such as secure land tenure, space for toilet construction, ability to use low-cost technologies,
and social factors, such as community cohesion that enables collective action and community
leadership, are supportive.
Collective behaviour (CLTS/SLTS) • Sanitation status: Most relevant in contexts where open defecation is prevalent, as these approaches
focus heavily on stopping open defecation towards a minimum level of service.
• Previous subsidies: may be challenging to implement where heavily-subsidised programmes have
been implemented, as household may expect external support for toilet construction.
• Sustainability: One-o ‘triggering’ may be insucient; further steps to ensure sustainability of open
defecation free status though sustained use of safe toilets that contain excreta by the entire community
and further progress towards a safe sanitation chain should be considered, drawing on other sanitation
promotion approaches.
• Culture: Provocative discussions about excreta as often practiced in CLTS to generate disgust (and
sometimes shame) can be instrumental in breaking taboos and generating change in some cultures,
while in others it can be counterproductive if considered too oensive or incompatible with local culture.
Adaptation of the methodology and good facilitation are needed.
• Peer pressure: While sometimes applied in CLTS to address open defecation, peer pressure may
unintentionally translate into coercion and exclusion. This can be avoided by ensuring sanitation
committees represent all groups in the community, and ensuring all households have the opportunity to
change their practice before peer pressure is applied.
• For SLTS: Assumptions that children will act as change agents to improve sanitation within their
household may not hold. Parallel community level approaches are needed.
These considerations have led to various adaptations, and combinations with other approaches. These
include combination with nancing approaches (e.g. subsidies), toilet upgrade schemes, increasing
supply (e.g. sanitation marketing), non-coercive self-monitoring mechanisms, and utilizing CLTS
approaches to trigger/mobilise communities and landlords in urban settings.
Social and commercial-marketing based approaches (Sanitation as a Business (SAAB), Sanitation Marketing (SanMark), Developing
Markets for Sanitation (DMS), Micro-nancing (loans), Targeted pre-construction hardware subsidies, Output-based subsidies)
Market-based approaches
(SAAB, SanMark, DMS)
• Context: Applicable to rural and urban contexts in areas connected to markets, supply chains and
marketing centres, and where a range of sanitation products are applicable to the context. Special
consideration is needed to each the poorest households with aordable technologies and services.
• Can be applied to both demand and supply sides:
o To secure supply in response to demand, e.g. when there is a lack of desirable products or when
adequate supply is a bottleneck for increasing coverage.
o To increase demand by using social marketing approaches to enhance the desirability of sanitation
and drive household investment in sanitation products.
• Capacity: Successful application requires in-depth knowledge of the market and the type of products
needed, as well as marketing expertise; implementation is therefore challenging in contexts where
these skills are absent or rare.
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Chapter 5
target population and target behaviours. Situation
analysis, research and consultations with experts
can help to identify which approach or combination
of approaches is likely to be most effective for a
specic context (see Section 5.4.2). For a strategy to
be successful, however, it needs to impact:
• uptake (e.g. construction and/or adoption of a new
sanitation facility);
• adherence (e.g. use of the sanitation facility over
time); and
• sustainability (e.g. long-term use and associated
maintenance and replacement).
These apply equally for strategies that aim to
change specific hygiene and sanitation practices
and behaviours, such as handwashing with soap at
key times, safe disposal of child faeces, and hygienic
pit emptying.
The success of the approaches detailed above
in driving and sustaining sanitation behaviour
change depends on their application within the
specic programme context. Table 5.1 lists the main
considerations for the application of each approach.
Given that IEC approaches are rarely used alone, but
incorporated into other approaches, they are not
discussed separately in the table.
5.4.2 Designing, adapting and delivering
behaviour change interventions
Developing and implementing a behaviour change
strategy is a multi-stage process (Figure 5.2) that
benets from the input of technical experts throughout
the process. The stages outlined present a general
set of activities that can be used to help plan and
organize the development and implementation of a
behaviour change intervention. Investing sucient
resources in designing a robust behaviour change
programme up front can save the costs of running
a programme that later proves to be ineective, as
many post-hoc evaluations have shown (Biran et al.,
2014). Similar steps can also be used to adapt existing
interventions. The adaptation may be operational
(i.e. how the intervention is delivered or managed) or
related to the content (i.e. the specic strategies and
materials developed and delivered).
Approach Considerations for implementation
Financing approaches:
Micro-nancing,
Targeted hardware subsidies,
Output-based subsidies
• Application: Usually coupled with promotional or supply-side interventions, rather than used as
standalone approaches.
• Sustainability: Scale up of subsidy schemes beyond a small-scale pilot can be challenging.
• Unintended consequences: Subsidies can lead to corruption or inaction by non-beneciaries;
comprehensive delivery of the scheme to all target beneciaries and clear and transparent rules are
crucial. Output-based subsidies that reward sanitation practices through community or household
incentives such as cash or vouchers are partially a response to the perverse incentives created by pre-
construction subsidies. Micro-loans, which are normally applied to productive ventures that enable
repayment can lead to increased indebtedness when applied to consumer products like toilets; use of
loans should be considered carefully where the targeted beneciaries include poor households and
those without sucient cash income.
Approaches based on psychological and social theories
Behaviour change campaigns • Research investment: Because they are newer than other models and contextually-specic, these
approaches require a higher investment in formative research and pre-intervention activities.
• Expertise: The specialized nature of these programs may also require additional expertise because they
often focus on activities and strategies that are not traditionally part of public health programs.
Table 5.1 Summary of approaches and factors for consideration in their implementation (continued)
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Documenting existing behaviours (situation analysis)
In order to design a sanitation behaviour change
intervention it is necessary to collate available
information on the sanitation situation and behaviours
within the target population. This involves reviewing
published and grey literature and consulting global
and local experts. It may include:
• examination of publicly available data sets (e.g.
DHS, MICS, census data);
• reviewing what is known about the drivers of the
target behaviour from the literature and previous
experience (e.g. KAP [Knowledge, Attitude and
Practice] studies, market studies, programme
evaluations); and
• consultation with key stakeholders from:
– relevant national and local ministries;
– civil society organizations
– subject matter experts, and
– local communities.
By consulting widely, existing interventions, policies
and strategies that could support the intervention
can be incorporated into the plan.
Following literature review and stakeholder consultation,
the situation analysis can be used to dene the specic
objectives of the intervention. These may be singular,
and organized around a specic behaviour, or they may
be broad and include multiple behavioural targets. In
general, behaviour change interventions that focus on
specic or a limited number of target practices have had
greater success than interventions that pursue multiple
behavioural objectives at once. In a limited number of
examples, large “umbrella” programs (which combine
multiple closely-related behaviour change targets
within a single overarching programme) have been
shown to be eective at eliciting behaviour change
(Fisher et al., 2011; Marseille et al., 2014), although
programmes with multiple objectives also run the risk
of message dilution without careful and deliberate
coordination (Greenland et al., 2016a).
The objective of the situation analysis step is, thus, to
identify and tightly dene the behaviours that need to
be targeted for change, and to set out what is known
and what is not known about the determinants of
these specied behaviours (Aunger & Curtis, 2016).
The unknowns then provide an agenda for research.
Understanding behavioural drivers
Context specic or formative research, which may
include quantitative, qualitative and participatory
methods, is useful in order to understand the
behaviour (both what people do now that is unsafe/
risky and the desired safe behaviour), within the
actual population (i.e. within the target households
Figure 5.2 Stages in behaviour change strategy design
Documenting
existing behaviour
• Situation analysis
• Surveys
• Nationally-
representative data
sets
• Stakeholder and
key informant
engagement
Understanding
behavioural drivers
• In-depth interviews
• Direct observations
• Interactive methods
Developing
the intervention
• Engagement of
relevant specialists
and stakeholders
• Content
development and
pre-testing
• Denition of
activities and
protocols
Testing intervention
delivery
• Behavioural trials/
trials of improved
practice
• Pilot projects
Implementation
• Delivery of
intervention at the
desired scale
• Regular review and
adaptation
• Evaluation
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and communities where the behaviour occurs) and
it should help to:
• document existing sanitation- and sanitation-
related behaviours within the target population;
• understand sanitation- and sanitation-related
behaviours from the perspective of the target
population;
• identify the most important determinants of the
target behaviour within the target population; and
• identify and understand the channels of
communication that best reach and inuence the
target populations.
This examination may suggest specific messaging
strategies or specific determinants that have the
potential to leverage the most change within
the population. Understanding the underlying
determinants of the behaviour of interest, how those
determinants can be changed to enable behaviour
change, and testing and adapting delivery strategies
can lead to sustained behaviour change and help ensure
that limited resources are used in the most eective way
possible. It also helps to avoid applying approaches
used successfully elsewhere when they are unlikely to
work in the given context (although learning from other
contexts can also oer valuable insights).
Creating a sanitation behaviour change intervention
Information gathered as part of the previous two steps
can be collated and organized using a framework for
understanding sanitation behavioural determinants.
Based on a clear understanding of the behaviour(s)
and behavioural determinants to be targeted by
an intervention, a draft theory of change can be
constructed. A theory of change oers a description of
how a specic change occurs within a specic context; it
often includes both text and a graphical depiction of the
causal pathway connecting programme or intervention
activities to the expected change.
A theory of change should reect the intervention
as planned. This includes both the intervention
content and its intended delivery mechanism, all of
which require careful consideration and coordination
among stakeholders. For a messaging campaign,
this includes selecting the key messages, articulating
how (and when) those messages are expressed to
the target population and defining what specific
determinants those messages are intended to change.
For community-based approaches, it is necessary to
specify the community-level activities that will be used
to foster change among participants and who will be
responsible for their implementation and delivery. For
interventions which provide subsidies to households, it
is necessary to dene the amount, the form or type of
subsidy (e.g. cash transfer, cash rebate, voucher, direct
distribution of goods), how they will be targeted (i.e.
inclusion and exclusion criteria) and distributed and
how they will be veried and outcomes monitored.
There are a range of specialists that can, and should, be
engaged in the process of intervention development,
and these may include individuals outside of the
traditional Ministry of Health and its partners. For
example, a creative team (rather than a health education
team) can be employed to craft an intervention that
is engaging, motivating and addresses the issues that
enable or prevent performance of the behaviour at
the individual-level in the context of the limitations
and realities of the structural environment (Aunger &
Curtis, 2016).
Testing, adapting and delivering a sanitation
behaviour change intervention
Interventions should be tested, as far as is possible,
before they are taken to scale. This can be done in
a variety of ways. Behavioural trials are small scale,
qualitative-focused projects in which new behaviours
are introduced to a group of people who are then left
to practice that behaviour on their own for a period
of time and their experiences and challenges then
documented. Trials of improved practices (TIPS) are a
formal methodology for introducing new behaviours
to a small group of participants and rigorously
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documenting adaptations, modications and barriers
to sustained use. The focus of both behavioural
trials and TIPs is program adaptation: results are
used to inform the development and modication
of a potential intervention or programme before
introduction to a wider audience. Pilot projects,
where the intended intervention is rolled out at a
small scale, can help to identify the feasibility and
mechanics of delivery for broader implementation.
For the intervention to be successful it needs to be
delivered as designed and in the frequency required.
Inconsistent, irregular or unspecified delivery of
behaviour change interventions is often associated
with sub-optimal outcomes (Huda et al., 2012;
Boisson et al., 2014).
There is a range of options for delivering a sanitation
behaviour change strategy to the target population;
delivery can be through a stand-alone, focused
behaviour change campaign or through integration
and coordination with other public health and
development initiatives.
Stand-alone sanitation campaigns can happen at
many levels, from local community-based initiatives
to national sanitation campaigns (such as the Swachh
Bharat Abhiyan in India). These campaigns may
involve the use of large numbers of frontline workers
focused on sanitation promotion, branded mass
media presence and a focus on delivering a primary
set of behaviour change messages to a population.
Advantages of a focused, stand-alone approach
include more control over programme messages,
coordination and management of programme
resources, along with improved opportunities for
monitoring progress and implementation. However,
national multiplayer integrated eorts may bear more
fruit in the longer run. Sanitation behaviour change
strategies can also be integrated into larger behaviour
change initiatives that focus on addressing multiple
population-level risk factors.
Alternative approaches to delivery of behaviour
change interventions involve integration into
existing public health and/or development
programmes such as health extension programmes,
healthcare services (e.g. immunisation or nutrition
programmes – Velleman, Greenland & Gautam
2013), or other public or private sector platforms
that reach and have inuence over the target group.
Integrated programmes often benet from existing
implementation and monitoring systems, which can
reduce start-up costs. Integrated strategies have the
potential to leverage synergies between dierent
public health initiatives. However, they also run the
risk of dilution or inconsistent messaging. Health
extension workers, in particular, are increasingly
targeted for delivering public health and behaviour
change interventions and the risk of over-extending
a limited and, often, voluntary workforce should not
be ignored. In addition, data on the eectiveness of
integrated programs is limited.
Regardless of the approach used, attention should
be given to the frontline workers who are engaged
in the direct delivery of sanitation behaviour change
activities. Frontline workers may require training,
capacity strengthening and supervision to ensure
that the intervention is delivered as designed. In
particular, current behaviour change approaches
require that these workers shift from traditional
educational approaches to new ways of working.
Case studies on CLTS in Lao PDR have found that
many frontline workers default to education and
awareness-based messages rather than utilizing
the range of community mobilization approaches
central to the CLTS approach and that district teams
felt they did not have sucient training to trigger
behaviour change (Baetings, 2012; Venkataramanan
et al., 2015). Similar problems were encountered
in Zambia (Greenland et al., 2016a). Retraining of
frontline workers in new approaches may thus
require substantial investment. The behaviour change
activities should extend but not overwhelm the world
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view and education level of those charged with
delivering it.
As indicated in Chapter 4, success is likely to be
dependent upon a number of factors, including an
enabling environment, government and stakeholder
support and alignment of policies and regulations,
and adequate funding.
5.5 Monitoring and learning for success
Monitoring and oversight of sanitation behaviour
change interventions should help to organize
stakeholders around common objectives and provide
systems for assessing progress. These efforts can
inform the adaptation and improvement of future
strategies through systematic learning. While
monitoring is an important element of sanitation
behaviour change programming, and has been
suggested as a powerful promotional tool, routine
and consistent monitoring data on behaviour change
is often lacking (Sigler, Mahmoudi & Graham, 2015).
Behaviour change monitoring should be consistent
with monitoring approaches used for other sanitation
interventions. There are potentially three distinct
types of monitoring necessary for successful
sanitation behaviour change programs (Pasteur,
2017). These include:
• process monitoring, which focuses on the quality
and eectiveness of intervention delivery;
• progress monitoring, which focuses on behaviour
change at the individual- and community-level; and
• post-intervention monitoring, which focuses on
sustained behaviour over time. Post-intervention
monitoring is particularly crucial to ensure the
elimination of open defecation and ensure
consistent use of facilities.
Standard approaches to measurement should be
incorporated into behaviour change monitoring and
contain clearly articulated denitions of behavioural
outcome, behavioural determinants, individual
exposure to, and participation in, behaviour change
intervention strategies and the total population
reached through behaviour change initiatives.
Dening consistent and clear indicators can ensure
that local organizations are both contributing to
larger behaviour change objectives and measuring
progress in a clear and consistent manner. However,
measuring sanitation behaviour can be complex and
the choice of measurement (Table 5.2) and method
will have resource implications.
Monitoring changes in behavioural determinants
should be done with caution. Determinants are
often abstract, latent concepts that present unique
measurement challenges. Developing valid and
reliable measures of these determinants can be time
and labour intensive (Dreibelbis et al., 2015). Some
behaviour change models provide standardized tools
for measuring specic determinants, but indicators
may need to be adapted to the local context and the
specic behaviour of interest.
Process and progress monitoring can not only ensure
that interventions are proceeding as planned, but
also inform programmatic adaptation and learning.
Sanitation behaviour change is not a singular, one o
event, but rather an ongoing process. Interventions
may be eective at raising awareness or changing
motivations, but not translate into individual
or collective changes of behaviour. Effective and
ecient monitoring should provide a clear indication
of when programme activities are not resulting in
expected changes within the target population, and
why change is not happening, to inform programme
adaptations or revisions when necessary. Programmes
should be designed and budgeted from the outset in
a way that mandates and enables regular review and
adaptation.
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WHO GUIDELINES ON SANITATION AND HEALTH
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Table 5.2 Behavioural monitoring methods and measures
Method Description Advantages Disadvantages
Direct observation Trained sta observe behaviours
in their natural environment and
document behaviours
Structured observations are
considered the “gold standard” of
behavioural measurement
Time, labour, and resource intensive
Potential for reactivity – individuals may over
perform during observation
(Ram et al., 2010; Arnold et al., 2015)
Requires training
Proxy indicators Readily observed or measurable
indicator that is assumed to have a
strong relationship with behaviour
of interest
Low cost
Can be easily integrated into
routine data collection
Relationship with behaviour not veried
Requires training
Self-report Respondent provides information
about behaviour
Low cost
Can easily be integrated into
routine data collection
High risk of overreporting
Limited ability to capture information about
anyone other than the respondent
(Jenkins, Freeman & Routray, 2014)
New experimental
approaches
Electronic sensors that capture
toilet use
Objective data (Clasen et al., 2012;
Thomas et al., 2013)
High cost
Resistance by end-users
Limited support for data processing, analysis
and interpretation
(Jenkins, Freeman & Routray, 2014).
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6.1 Introduction
Sanitation interventions and the safe disposal of
human excreta have the potential to impact on the
transmission of a diverse range of microbial hazards.
This chapter outlines the characteristics of the four
main groups of pathogenic hazards (bacteria, viruses,
protozoa and helminths) considered within these
guidelines, and examines their transmission pathways
and how infection relates to poor sanitation. The
importance of sanitation for control of pathogens
varies depending on their size, persistence in the
environment and their infectivity. Further information
is provided in section 6.3.4. Specic information on
individual pathogens is summarised in Table 6.1, and
additional information can be found in the Global
Water Pathogen Project (GWPP), which is available
online (www.waterpathogens.org).
6.1.1 Bacteria
Bacteria are small (typically 0.2-2 micrometres)
single celled organisms, many of which are capable
of multiplication outside a host under favourable
conditions. Most bacteria considered here are
enteric, transmitted by the faecal-oral route, and
predominantly cause gastroenteritis. Some can cause
severe health outcomes and may have long-term
eects. While multiplication of pathogenic enteric
bacteria in the environment is possible, it is rare.
Although many enteric bacteria are zoonotic (i.e. they
can be transmitted from animals to humans) the safe
disposal of animal faeces is beyond the scope of these
guidelines. Bacteria have the ability to enter a viable
non-culturable state that allows them to persist in the
environment for long periods of time.
Bacteria may develop antimicrobial resistance
(AMR), where they become resistant to the eects of
antibiotics, biocides and so on. While the development
of AMR is a natural phenomenon, it can be accelerated
by the selective pressure exerted by the use and misuse
of antimicrobial agents in people and animals, and by
their environmental release (e.g. antibiotics entering
wastewater either unused as waste or (un)metabolized
after therapeutic use). Exposure to antibiotic resistant
bacteria may lead to infections that are hard, or even
impossible, to treat (see Box 6.1).
6.1.2 Viruses
Viruses are simple infectious agents, consisting
only of genetic material (DNA or RNA) encased in a
protein capsid. They are the smallest (typically 20-100
nanometres) organisms considered here and they
are obligate intracellular organisms (i.e. they must be
within a susceptible host cell to reproduce). Viruses
can be excreted in very high numbers and may be
transported long distances in water. Viruses cannot
metabolize in the environment, so their persistence
typically depends upon the extent to which the protein
capsid can remain intact under adverse environmental
conditions. The viruses covered in this chapter are
enteric and predominantly lead to gastroenteritis
(although some virus types can lead to other health
outcomes such as hepatitis and viral meningitis).
6.1.3 Protozoa
Parasitic protozoa are complex and relatively large
(typically 3-20 micrometers) single celled organisms
that cannot replicate outside a suitable host. Those
covered in this chapter are enteric and cause
gastroenteritis of varying duration and severity.
Chapter 6
EXCRETARELATED PATHOGENS
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CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
Box 6.1 Antimicrobial resistance and sanitation
Antimicrobial resistance (AMR) among human pathogens has been
identied by the World Health Organization as one of the greatest
global threats to human health. AMR arises from genetic mutations
that allow the emergence of new bacterial strains that are not aected
by an antimicrobial agent. This can occur in the body of a host or in
environmental settings where the presence of an antimicrobial agent
kills o the main populations of the target bacteria and allows the
remaining resistant strains to ourish. In the environment, genetic
material (such as plasmids) that includes the genes that code for
AMR can be exchanged between metabolizing and/or replicating
bacteria, thus spreading the AMR attributes across diverse populations
of environmental bacteria and pathogens.
AMR is common among environmental bacteria, including in pristine
locations relatively untouched by modern anthropogenic activities,
such as caves, permafrost, and glaciers. However, use of antibiotics in
humans, livestock and companion animals has been associated with
evolution and amplification of antibiotic resistant pathogens and
the antibiotic resistance genes (ARGs) that they carry. Environmental
reservoirs are the primary source of ARGs and anthropogenic activities
are increasing the importance of the environment as a pathway for AMR
human exposure. For example, human consumption of antibiotics can
contribute antibiotics, resistant pathogens and ARGs to waterways via
faecal contamination resulting from open defecation, discharge of raw
and treated sewage, septic tank seepage, and seepage from toilets. In
particular, wastewater from hospitals and antibiotic manufacturing
facilities are likely to contain elevated concentrations of antibiotics
and resistant pathogens.
Use of antibiotics in livestock can also contribute antibiotics and
clinically-relevant ARGs to waterways via runo from feedlots or from
manure-treated elds. Exposure to AMR pathogens may occur when
humans come into contact with water downstream of these sources.
For example, wastewater reuse, recreational water use, consumption
of contaminated drinking water, and aerosolization of contaminated
water for non-drinking purposes such as irrigation, toilet ushing, or
cooling towers, may all serve as possible routes of exposure to AMR
bacteria and other pathogens. Consumption of contaminated food
products can also facilitate spread of AMR from agricultural sources.
Further research is needed to better understand the circumstances that
promote the development and dissemination of AMR among bacteria
in the environment and how to prevent this.
Safe sanitation systems and hygiene practices can serve as critical barriers
between sources of AMR and human exposure. Hand washing can limit
AMR spread via inter-personal contact, while safe toilets, containment,
conveyance, treatment (of wastewater and sludge) and safe end use and
disposal as well as drinking water treatment and source water protection,
are all critical barriers that can prevent the transmission of AMR pathogens
from faecal sources to humans. In addition, population-level interventions
can reduce the problem of AMR by limiting antibiotic prescription,
increasing public outreach and communication about appropriate
antibiotic usage, and establishing policies that limit unneeded antibiotic
use or discharge of contaminated wastes.
Adapted from original work by Emily D. Garner and Amy Pruden, Virginia Tech.
Unsafe/non-existing (or not used) toilets
Unsafe containment storage/treatment
Unsafe conveyance/transportation
Unsafe o-site treatment
Hospital wastewater
Agricultural wastewater, manure and runo
Sources
Wastewater from antibiotic manufacturing
Interventions
Public outreach and communication
Source controls through reducing use
Policy, regulations and standards
Environmental reservoirs
Water
Soil and sediment
Air
Exposure
Wastewater, manure and excreta use in agriculture
Aerosols
Recreational water use
Food crops
Entire community access and use of toilets that
safely contain excreta
Hand washing
Safe sanitation chains in all settings (particularly
safe treatment of wastewater and faecal sludge)
WASH barriers
Safe use of wastewater, excreta and manure in
agriculture
Safe drinking water
WASH, environmental cleaning and waste
management in health facilities
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WHO GUIDELINES ON SANITATION AND HEALTH
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While excretion densities are orders of magnitude
lower than viruses, the production of robust cysts
or oocysts enhances survival in the environment.
Cryptosporidium spp., Giardia spp. and Entamoeba
histolytica are all infective upon excretion, while
Cyclospora oocysts require a latency period of some
days for maturation in the environment.
6.1.4 Helminths
Helminths (also known as parasitic worms) include
tapeworms (cestodes), flukes (trematodes) and
roundworms (nematodes). They are multi-cellular,
complex organisms. Some helminths, referred to as
soil-transmitted helminths (STH), can be transmitted
by the faecal-oral route (after a period of maturation
in the environment), with infection being caused
by ingestion of fertile worm eggs or through skin
penetration by infective larvae.
Although STH infections are often largely
asymptomatic, they can lead to various mild to
serious effects such as chronic abdominal pain
and diarrhoea, iron deficiency anaemia, growth
faltering, recurrent rectal prolapse, bowel/intestine
obstruction, appendicitis, pancreatitis and protein
energy malnutrition. Excretion of infective eggs
can be abundant (see Table 6.1). In some species,
especially Ascaris lumbricoides, eggs can survive in
the environment for years where soil conditions are
favourable.
6.2 Microbial aspects linked to
sanitation
The role of poor sanitation and excreta in disease
transmission depends on the individual pathogen. In
the simplest categorization, there are three primary
ways in which human excreta may increase the
occurrence of human infections:
• as a source of enteric pathogens in the environment;
• by contributing to excreta dependent lifecycles; and
• by facilitating vector breeding.
This section briey introduces these and then outlines
the most important excreta-related pathogens (Table
6.1).
6.2.1 Excreta as a source of enteric pathogens in
the environment
Enteric pathogens colonize the intestine, multiply
within infected individuals (except helminths, which
do not multiply but lay eggs), and are subsequently
excreted (potentially in large numbers) with faeces.
Every excreted infectious pathogen has the potential
to cause a new infection if ingested by another person
(i.e. faecal-oral transmission). Potential exposure
pathways are illustrated in Figure 6.1 and include:
• Fingers: Pathogens may be transferred to ngers
through touching of faeces or faeces- contaminated
surfaces or people and then, subsequently, cause
infection as a result of putting ngers in the mouth
or nose, or on food.
• Food: Fresh produce can become contaminated
through the use of wastewater for irrigation, faecal
sludge for fertilizing or the use of contaminated
wash water. When consumed raw (or lightly
cooked) the produce can contain infectious
pathogens.
• Drinking-water: Drinking-water from surface and
groundwater sources can be contaminated with
faecal pathogens.
• Hygiene and household water: Faecally
contaminated water used for washing and food
preparation, while consumed in smaller quantities
than drinking-water or unintentionally, can also
lead to exposure to faecal pathogens.
• Surface water: Playing or bathing in contaminated
surface waters may lead to unintentional ingestion
of water and subsequent infection. Similarly,
occupational exposure (e.g. fishing, vehicle
washing) can lead to ingestion of surface water.
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CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
Faeces-contaminated water may become aerosolized
through spraying, ushing or washdown activities.
Aerosols may be inhaled into the nose or mouth with
regular breathing and can be swallowed with saliva
or nasal secretions.
The focus and objective of a safe sanitation system is
to interrupt all the exposure pathways. An individual’s
risk of infection from enteric pathogens is driven
by their overall exposure via all pathways, thus the
impact of a single pathway on a community’s burden
of disease can be dicult to isolate. Specic sanitation
interventions, from toilet construction to safe disposal
or use of faecal matter, will impact on each of the
pathways in dierent ways. The relative magnitude of
each exposure pathway will depend on:
• the individual characteristics of each pathogen;
• the location and setting;
• the local environmental conditions driving
transport and persistence of pathogens; and
• the endemic rate of disease driving the occurrence
of pathogens in faeces.
An individual’s activities (e.g. occupational risks for
workers, household risks for those responsible for daily
activities such as washing and food preparation, and
personal hygiene) will ultimately inuence exposure.
Any sanitation intervention can be expected to reduce
exposure to microbial hazards, but the extent of that
reduction will vary depending on the pathogen,
setting and individual. The impact of that reduction
on the overall incidence of disease will depend upon
the magnitude of other remaining exposure pathways
(Robb et al., 2017).
Human host
Sanitation hazards
Hazardous events Exposure
Disease outcome
(See table 1.1)
Faeces
Urine
Face
Mouth
Feet
Feet/skin
Fingers
Water
consumption/use
Animals*
Water
bodies/drains
Unsafe
(or non-existing/unused)
toilets
Unsafe end
use/disposal
Unsafe o site
treatment
Unsafe
conveyance/
transportation
Unsafe
containment
(storage/treatment)
Flies
Crops/food
Objects/oors/
surfaces
Ground
water
Fields
Figure 6.1 Transmission of excreta-related pathogens
* Refers to animals as mechanical vectors. Transmission of animal excreta-related pathogens to human hosts is not represented in this diagram.
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WHO GUIDELINES ON SANITATION AND HEALTH
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6.2.2. Excreta dependent pathogen life cycles
For some pathogenic helminths, the transmission
pathway for infection is complex. For these organisms
a life cycle involving broader ecological interactions
exists.
The overall management objective is to break the life
cycle and prevent re-infection. Sanitation that prevents
the release of untreated excreta into the environment
is a necessary control point for breaking the ongoing
cycle of worm reproduction (for example, for
Schistosoma spp., STH and tapeworms). Other control
points include management of snail populations,
minimizing water exposure, maximizing drug therapy
for infected individuals (e.g. for Schistosoma spp.
and STH) and improving food hygiene and animal
husbandry practices for tapeworms.
6.2.3 Excreta facilitated vector breeding
Unsafe disposal of excreta including open defecation,
unprotected pit latrines and poorly draining water
systems, can facilitate vector breeding. Insects (e.g.
ies, cockroaches and mosquitos) can act as vectors
of disease by mechanically transporting pathogens in
the environment, either on their bodies or within their
intestinal tract.
Solid faecal waste that is not safely contained can
provide a habitat for flies and cockroaches. There
is a broad body of evidence showing that insects
which breed in excreta, or feed on it, may carry human
pathogens on their bodies or in their gut (see the
review by Blum & Feachem, 1983 and subsequent
studies: Feachem et al., 1983; Graczyk, Knight &
Tamang, 2005; Tatfeng et al., 2005; Gall, 2015). For
example, cockroaches trapped from the toilets of
houses with pit latrines had mean microbial counts
of 12.3 ×10
10
bacteria/ml and 98 parasites/ml, with
the microorganisms representing a wide range of
faecal-oral pathogens (Tatfeng et al., 2005). Insects
can, therefore, enhance the faecal-oral transmission
of pathogens by providing additional pathways from
excreta to food and/or kitchen utensils.
Flies have been shown to carry a variety of enteric
pathogens including bacteria and protozoa (Khin,
Sebastian & Aye, 1989; Fotedar, 2001; Szostakowska
et al., 2004). In addition to faecal-oral transmission of
particular pathogens, ies are a key mechanism for
transmission of ocular strains of Chlamydia trachomatis,
the causative agent of trachoma. Infection spreads
through passage of eye and nose secretions from
an infected individual via personal contact (ngers,
fomites) and certain species of ies (especially Musca
sorbens, which lays eggs on human faeces left exposed
on the soil). A meta-analysis (Stocks et al., 2014) found
evidence to support the role of water, sanitation and
hygiene as important components of an integrated
trachoma elimination strategy.
The importance of mosquito-borne diseases for public
health is widely documented. Unsafe sanitation and
improper drainage leading to stagnant water or
ponds can contribute to mosquito (particularly Culex
spp.) breeding, and hence the risk of mosquito-borne
diseases such as West Nile virus, lymphatic lariasis
Curtis et al., 2002; van den Berg, Kelly-Hope & Lindsay,
2013).
Safe sanitation systems must ensure that excreta are
contained in a manner that prevents insect oviposition,
and that allows the appropriate draining of water to
prevent breeding of mosquitos.
6.2.4 Excreta-related pathogens
Table 6.1 outlines key excreta-related pathogens where
sanitation is (or may be) important for the control of
infection.
105
CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
Table 6.1 Excreta-related pathogens (main source: Mandell, Bennett & Dolin, 2009)
Pathogen Health
signicance
Transmission
pathways
Important
animal
source
Likely
importance
of sanitation
for control
†
Concentration
excreted in
faeces**
Duration of
excretion
Additional
references
BACTERIA
Campylobacter spp. Most common
bacterial cause
of diarrhoea. Can
be associated
with serious
sequelae.
Predominantly
food and water
from animal
contamination.
Person-to-person
transmission
uncommon.
Poultry
and other
domestic
livestock
Low 10
6
– 10
9
/g Up to 3 weeks
Clostridium difficile Common cause
of diarrhoea
globally,
predominantly in
elderly patients.
Important cause
of antibiotic-
associated
diarrhoea.
Person-to-person
transmission,
predominantly
in care settings
through poor
hygiene practices.
Outbreaks seen
in institutional
settings.
None known Low —* —*
Enteroagglomerative
Escherichia coli
Important
cause of chronic
diarrhoea in
low-income
countries.
Uncertain Uncertain Uncertain — —
Enterohaemorrhagic
E. coli
Although not
common, high
risk of mortality
and severe
sequelae.
Person-to-person,
food borne and
waterborne.
Livestock High — —
Enteroinvasive
E. coli
Causes watery
diarrhoea but
can progress
to dysentery
(bloody
diarrhoea).
Associated
with foodborne
outbreaks
although person-
to-person spread
also occurs
Uncertain Medium — — Hunter, 2003
106
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 6
Pathogen Health
signicance
Transmission
pathways
Important
animal source
Likely
importance
of sanitation
for control
†
Concentration
excreted in
faeces**
Duration
of
excretion
Additional
references
Enteropathogenic
E. coli (EPEC)
Leading cause of
infant diarrhoea
in low-income
countries. Can
cause severe
diarrhoea.
Person-to-person No known
zoonotic source
High — May be
prolonged
Enterotoxigenic
E. coli (ETEC)
Leading cause
of childhood
diarrhoea in low-
income countries.
Common cause
of travellers’
diarrhoea.
Predominantly
food and
waterborne;
not thought to
be person-to-
person.
Can lead to
diarrhoea in
piglets and
calves; some
evidence on
transmission
from animals
but not a major
cause.
Medium — — Gonzales-Sile
& Sjöling, 2016
Helicobacter pylori Causes acute
gastritis and peptic
ulcers; major
risk factor for
stomach cancer (an
important cause of
cancer mortality
in low-income
countries).
Person-to-
person (crowded
conditions,
poor hygiene)
and faecal-oral
(untreated water,
poor sanitation).
None known Uncertain — —
Salmonella enterica
ser. Typhi
Typhoid (enteric
fever) is a severe
disease which if
left untreated has
high mortality.
Food and
waterborne
transmission
Restricted to
humans
High — May be
extremely
prolonged
Other Salmonella
strains
Range of
symptoms
(watery diarrhoea
to dysentery);
associated with
range of severe
systemic sequalae.
Predominantly
foodborne but
waterborne
outbreaks
have occurred.
Person-to-person
transmission
also occurs
(predominantly
in carers, e.g.
mother of a child
with infection or
health workers).
Predominantly
zoonotic
(poultry, pigs
and many
others).
Low Large variation Median
5weeks
Table 6.1 Excreta-related pathogens (continued)
107
CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
Pathogen Health
signicance
Transmission
pathways
Important
animal source
Likely
importance
of sanitation
for control
†
Concentration
excreted in
faeces**
Duration
of
excretion
Additional
references
Shigella
dysenteriae
Causes severe
diarrhoea and
dysentery with
signicant
consequences
including colitis,
malnutrition, rectal
prolapse, tenesmus,
reactive arthritis
and central nervous
system eects.
Person-to-person
(direct or indirect)
transmission; highly
infectious. Mostly in
low-income country
settings. Can cause
outbreaks.
None - strict
human pathogen.
High — —
Shigella flexneri Causes diarrhoea
and dysenteric
symptoms.
Person-to-person
(direct or indirect)
transmission and
highly infectious.
Mostly in low-
income countries.
Can cause outbreaks.
None - strict
human pathogen
High — —
Shigella sonnei Common cause of
watery diarrhoea
globally.
Person-to-person
(direct or indirect)
transmission and
highly infectious.
Can cause outbreaks.
None - strict
human pathogen.
High 10
6
– 10
8
/g Usually up
to 4 weeks
Vibrio cholerae Causes acute watery
diarrhoea which
can be very severe,
leading to death by
dehydration. Causes
outbreaks. Most
infected individuals
are asymptomatic.
Predominantly food
and waterborne.
Some person-to-
person transmission.
Some
transmission
linked to
uncooked seafood.
High Asymptomatic
10
2
– 10
5
/g;
Symptomatic
10
6
– 10
9
/ml
7 – 14
days
Eddleston
et al., 2008
Yersinia
enterocolitica
Causes watery
diarrhoea and
mesenteric adenitis
(inammation
of abdominal
lymph nodes, at
times mistaken
for appendicitis).
Not a commonly-
diagnosed cause
of diarrhoea.
Food and
waterborne
transmission, some
person-to-person
transmission.
Livestock, wild
animals and birds.
Medium — —
Table 6.1 Excreta-related pathogens (continued)
108
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 6
Pathogen Health
signicance
Transmission
pathways
Important
animal source
Likely
importance
of sanitation
for control
†
Concentration
excreted in
faeces**
Duration
of
excretion
Additional
references
AMR opportunistic
pathogens that
may be part of
normal faecal flora
(e.g. carbapenem-
resistant
organisms and
Enterobacteriacea
carrying extended
spectrum
betalactamases)
Colonizing the
intestines, causing
a wide range of
extraintestinal
infections in
vulnerable
individuals and
populations, e.g.
blood stream
infections including
sepsis (neonatal,
postpartum,
postoperative, in
immunosuppressed
individuals), urinary
tract infections,
postoperative
surgical site
infections.
Person-to-person
(direct or indirect)
transmission;
highly infectious.
Mostly in low-
income country
settings. Can cause
outbreaks.
None - strict
human
pathogen.
High — —
VIRUSES
Adenoviruses A large group of
distinct viruses
that cause a variety
of conditions.
Genotypes 40 and
41 predominantly
cause gastroenteritis
in children, resulting
in prolonged
diarrhoea (up to 10
days).
Person-to-person,
through both
faecal-oral
and droplet
transmission.
None – strict
human
pathogen
Low 10
11
/g
(lower with
non-enteric
adenovirus)
Months
after
symptoms
resolve
Astroviruses Common cause of
diarrhoea globally,
especially in young
children.
Predominantly
person-to-person,
potentially
waterborne.
Outbreaks
usually occur
in institutional
settings.
None – strict
human
pathogen
Low 10
2
– 10
15
/g Up totwo
weeksafter
symptoms
end
Vu et al.,
2017
Enteroviruses Large number of
viruses with a vast
array of clinical
symptoms (including
poliovirus – see
below).
Person-to-person
and environmental
exposure
None known Uncertain up to 10
6
-10
7
/g 10 days to
2 months
Table 6.1 Excreta-related pathogens (continued)
109
CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
Pathogen Health
signicance
Transmission
pathways
Important animal
source
Likely
importance
of
sanitation
for control
†
Concentration
excreted in
faeces**
Duration of
excretion
Additional
references
Hepatitis
A virus
Causes acute,
usually self-
limiting hepatitis.
Occasionally
associated with
death from acute
liver failure.
Food and
waterborne; person-
to-person. Both
routes can lead to
outbreaks
No (non-human
primates have been
infected in studies
but are not part of
the transmission
cycle).
Medium Prevalence
in stool
higher before
symptoms.
Present from
14-21days
before
onset to
8days after
appearance
of jaundice.
Hepatitis E
virus
Can cause
acute hepatitis;
genotype 1
associated
with maternal
mortality in
low- and middle-
income countries
due to acute liver
failure.
Genotypes 1
and 2 dominate
in LMIC and are
predominantly
waterborne.
Genotypes 3 and 4
dominate in Europe
and are associated
with consumption of
contaminated pork
or game meat.
Genotypes 1 and 2:
no known animal
transmission
pathway.
Genotypes 3 and
4 are zoonotic,
strongly linked with
pork consumption.
Medium 10
5
/ g- 1 week
before
symptoms
up to
4weeks
following.
Chaudhry
et al., 2015;Park
et al., 2016
Noroviruses Leading cause of
gastroenteritis
outbreaks
(characterized
by diarrhoea,
vomiting and
stomach pain) in
all age groups.
Predominantly
person-to-person
through both faecal-
oral and droplet
transmission; can
be spread through
food and water.
Major cause of
sporadic outbreaks
in hospitals,
nursing homes and
other institutional
settings.
None – strict
human pathogen
Low 10
11
/ g 8 –60 days
Polioviruses Acute poliomyelitis
is frequently
asymptomatic. A
small proportion of
people will develop
paralysis.
Person-to-person.
Some outbreaks
have been associated
with breakdown
in sanitary
infrastructure (e.g.
during war)
None – strict
human pathogen
Medium — — WHO
(undated a)
Table 6.1 Excreta-related pathogens (continued)
110
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 6
Pathogen Health
signicance
Transmission
pathways
Important
animal source
Likely
importance
of
sanitation
for control
†
Concentration
excreted in
faeces**
Duration
of
excretion
Additional
references
Rotaviruses Major cause of acute
gastroenteritis in
infants globally.
Common symptoms
include severe
watery diarrhoea,
vomiting, fever and
abdominal pain.
Rotavirus infection is
associated with severe
dehydration and
occasionally death.
Person-to-
person.
Most rotaviruses
are strict human
pathogens;
group Crotavirus
may be
associated with
cattle.
Low 10
10
–10
12
/ g 2 days
before to
10days after
symptomatic
illness.
Meleg et al.,
2008
Sapoviruses Cause of acute
diarrhoea and
vomiting globally.
Predominantly
person-to-person
through both
faecal-oral
and droplet
transmission;
can be spread
through food and
water.
None – strict
human
pathogen
Low — — Chaudhryet
al.,2015; Park
et al., 2016
PROTOZOA
Cryptosporidium spp. One of the most
common causes
of diarrhoea in
young children
globally. Diarrhoea
can be prolonged
(several days or
more) especially in
immunocompromised
individuals.
Person-to-
person, and there
is a large number
of foodborne
and waterborne
outbreaks.
Of the two
main species,
C. parvum can
infect multiple
species, and the
main reservoir is
cattle.
C.hominis is
restricted to
humans.
High — — Hunter &
Thompson,
2005
Cyclospora
cayetanensis
Uncommon cause
of acute diarrhoea
and persistent in all
ages. Acute illness
can last between 1 to
8weeks.
Waterborne
and foodborne,
including
outbreaks.
Humans are the
only natural
hosts; animal
transmission
uncertain.
Low Up to 10
4
/g —
Entamoeba
histolytica
Can cause diarrhoea,
amoebic dysentery
and liver abscesses or
metastatic abscesses.
Common and patchy in
distribution.
Foodborne
waterborne,
infrequently
person-to-
person.
None High Up to 10
7
cysts/
day
Can be
prolonged
Table 6.1 Excreta-related pathogens (continued)
111
CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
Pathogen Health
signicance
Transmission
pathways
Important
animal source
Likely
importance
of
sanitation
for control
†
Concentration
excreted in
faeces**
Duration of
excretion
Additional
references
Giardia
intestinalis
Most common
human protozoan
gastrointestinal
pathogen. Common
cause of diarrhoea.
Can be prolonged and
associated with growth
faltering in children
and weight loss in
adults.
Typically
waterborne,
also person-to-
person.
Various animal
hosts, including
wild animals,
dogs, cats, cattle,
pigs and chickens,
associated with
transmission of
some strains.
Medium 2 x 10
5
cysts/ g Can be
excreted
over several
weeks
Hunter &
Thompson,
2005;Laloo &
White,2013
HELMINTHS
Ascaris
lumbricoides
(roundworm)
One of the most
common human
helminth infections
globally. Largely
asymptomatic.
Can lead to bowel/
intestine obstruction,
appendicitis,
pancreatitis and
malnutrition.
Via consumption
of contaminated
soil and food,
and hand
contamination.
Evidence that both
Ascaris lumbricoides
and the pig Ascaris
suum can infect
humans, and
moreover the two
can also hybridize
together
High 10
5
eggs/g While
infection
persists
Bethony et al.,
2006
Anderson &
Jaenkike, 1997
Diphyllobothrium
latum
Intestinal tapeworm;
largely asymptomatic.
Can lead to anaemia.
Foodborne -
consumption
of infected sh
(eggs excreted
in human faeces
consumed by
small crustaceans
that are eaten
by smaller
sh; these are
consumed by
larger sh, which
are consumed by
humans).
Freshwater
crustaceans are
rst intermediate
host; Fish are the
second and third
intermediate
hosts. Many other
mammals (apart
from humans) can
serve as denitive
host.
Medium Up to1 million
eggs/ worm/
day
— Scholz et al.,
2009
Hookworm
Ancylostoma
duodenale
Necator
americanus
Largely asymptomatic.
Can lead to chronic
abdominal pain, iron
deciency anaemia
and protein energy
malnutrition.
Most relevant
transmission
pathway is skin
penetration (e.g.
walking barefoot
on contaminated
soil).
Ancylostoma
duodenale
can also be
transmitted
through the
ingestion of
larvae (on soil
and crops).
There are animal
hookworm species
that can infect
humans.
High Up to perhaps
50,000 eggs/g.
While
infection
persists
Bethony et al.,
2006.
Table 6.1 Excreta-related pathogens (continued)
112
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 6
Pathogen Health
signicance
Transmission
pathways
Important
animal source
Likely
importance
of
sanitation
for control
†
Concentration
excreted in
faeces**
Duration
of
excretion
Additional
references
Hymenolepis
spp. (dwarf
tapeworm)
Symptoms usually
mild; might include
abdominal pains and
anorexia in heavy
infections.
Humans are infested by
ingesting fertile eggs
from contaminated
food, water, soil and
surfaces.
Rodents (minor
importance)
High Uncertain Uncertain/
may be
years
CDC, 2012
Schistosoma
haematobium
Largely concentrated
in LMIC. Acute
illness: skin rashes,
blood in the urine,
anaemia. Chronic
illness: stunting,
renal problems,
hydronephrosis,
bladder cancer,
infertility, dyspareunia
,female genital
schistosomiasis,
bewteen cancer
and infertility. Can
also cause severely
contracted bladder.
Skin penetration
by cercariae in
contaminated water via
life cycle involving snail
host.
Some evidence
of rodents
for pure S.
haematobium.
Extensive
evidence
of livestock
contributing to
human infection
through viable
hybridization
of animal
schistosome
species with
S.haematobium.
High Excretion in
urine (though
zoonotic
hybridized
pairs may be in
both urine and
faeces). Each
worm pair can
produce several
hundred eggs
per day.
Uncertain Webster
etal., 2016
Leger &
Webster,
2017
Catalano S
et al., 2018
Other
Schistosomaspp.
(S.mekongi,
S.japonicum,
S.mansoni,
S.interculatum,
S.guineensis)
Abdominal pain,
anaemia, growth
faltering, epilepsy,
portal hypertension.
Skin penetration
by cercariae in
contaminated water via
life cycle involving snail
host.
Major role
of animals
(particularly
bovines,
rodents and/
or canines) for
S.japonicum and
S.mekongi Asian
schistosomes. In
Africa, rodents
and non-human
primates
can serve as
reservoirs for
S. mansoni.
Hybridized
animal intestinal
schistosomes
can infect
humans.
High Excretion in
faeces. Each
worm pair can
produce from
several hundred
eggs per day
(S.mansoni)
to several
thousand
eggs per day
(S.japonicum).
Uncertain
(can be
up to
30/40
years)
Webster et
al., 2016
Rudge etal.,
2013
Strongyloides
stercoralis
Abdominal pain,
bloating, heartburn,
diarrhoea,
constipation, cough,
rashes. Potentially
arthritis, kidney
problems and heart
conditions.
Can remain
asymptomatic
for decades. Vast
majority of infections
asymptomatic.
Infection by
infectious larvae
from contaminated
soil through skin
penetration.
Autoinfection (self-
reinfection) can occur,
which accounts for
prolonged carriage
after primary infecting
episode.
None High Depends on the
load and nature
of infection.
While
infection
persists.
Table 6.1 Excreta-related pathogens (continued)
113
CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
Pathogen Health
signicance
Transmission
pathways
Important
animal source
Likely
importance
of
sanitation
for control
†
Concentration
excreted in
faeces**
Duration
of
excretion
Additional
references
Taenia solium
(pork tapeworm)
Tapeworm
infection can cause
taeniasis1leading
to minor health
impacts, or
cysticercosis (if
a human is the
intermediate host)
in the muscles, skin,
eyes and the central
nervous system, with
potentially severe
health impacts.
Foodborne - taeniasis
caused by ingestion of
larvae in undercooked
pork; larvae develop into
mature worms in the
human body and eggs
are passed in faeces.
Person-to-person (poor
hygiene), food, water,
soil: Cysticercosis caused
by egg ingestion; eggs
form cysts in body
tissues. An individual
with a pork tapeworm
can be a source of
eggs for themselves
or anyone at risk of
ingesting their faeces.
Pigs are
the usual
intermediate
hosts, infected
through
consumption of
eggs excreted in
human faeces.
High 1 or a few
proglottids
2
lled with eggs
While
infection
persists
WHO
(undated
b); Webber,
2005
Taenia saginata
(beef tapeworm)
Taeniasis leading to
minor health impacts.
Foodborne - taeniasis
caused by ingestion of
larvae in undercooked
beef; larvae develop
into mature worms in
the human body.
Cattle are
intermediate
hosts, infected
through
consumption of
eggs excreted in
human faeces.
High 1 or a few
proglottids
lled with eggs
While
infection
persists
WHO
(undated
b); Webber,
2005
Trematode
(atworm)
parasites or
ukes
Fasciola hepatica,
F. gigantica (F)
Clonorchis
sinensis (C)
Opisthorchis
viverrini (O)
Paragonimus
ssp (P), most
common: P.
westermani, P.
heterotremus, P.
philippinensis
(F), (C) and (O)
cause liver uke
disease and (P)
cause lung uke
disease all largely
asymptomatic at
low. With heavy
infection; (F) leads to
chronic liver brosis
and pancreatitis,
(C) and (O) lead to
liver and bile duct
inammation and
brosis and bile duct
cancer in chronic
cases, (P) chronic
cases cause cough
with blood-stained
sputum, chest pain
with dyspnoea
and fever - pleural
eusion and
pneumothorax
are possible
complications.
All foodborne through
contamination of
freshwater (and
freshwater vegetation)
by human or animal
faeces. All have aquatic
snails as intermediate
hosts. Fish ((O),(C)),
crustaceans (P) are
second intermediate
hosts for metacercariae;
aquatic plants
provide substrate for
(F) metacercariae.
Ingestion of infected
raw aquatic vegetables
(e.g. water cress) (F);
of infected uncooked
or partially processed/
cooked sh (C) and (O),
or crustaceans (e.g.
prawns) (P).
Fish-eating
carnivores
(C) and (O);
crustacean-
eating
carnivores (P);
cattle, sheep,
bualoes, pigs,
donkeys (F).
Reduction of
contamination
freshwater
bodies by
parasite
eggs; animal
sources of
contamination
largely
predominant
Several
hundreds
to several
thousands with
each stool,
depending
on infection
intensity
While
infection
persists
(O) Sripa,
2003;
(O) and (C)
Sithithaworn
et al., 2011;
(F), (C),
(O) and (P)
Fuerst et al.,
2012;
Kim et
al., 2011;
Heyman et
al. 2015
Table 6.1 Excreta-related pathogens (continued)
114
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 6
6.3 Environmental transmission of
pathogens in faecal waste
For any of the transmission pathways (Figure 6.1) to
result in additional infections in the population, the
pathogens must be excreted in sucient quantities,
persist in the environment (e.g. on surfaces, water,
sewage and soil) and be transported (e.g. through
hand transfer, aerosol generation, contamination
of food crops or contamination of water sources),
in an infectious state, to a point of exposure. The
overall risk to human health is, therefore, driven
by the occurrence (i.e. the amount excreted into
the environment by infected people), pathogen
persistence in the environment (i.e. the probability
of their survival or of remaining infectious), the
presence and abundance of any required vectors
or intermediate hosts, and the infectivity of the
individual pathogens. Following an introduction
to pathogen detection methods, an overview of
the main data sources and principles of pathogen
occurrence, persistence and infectivity is provided
below. Further details and information are provided
in the relevant chapters of the GWPP.
6.3.1 Methods for detecting pathogens in
environmental samples
Microbiological analyses of environmental
samples collected in studies of sanitation usually
focus on bacterial or phage indicators of fecal
contamination – such as E. coli, enterococci, and
more recently, bacteroides phage (Diston et al.,
2012). These indicators are not perfect surrogates
for the persistence, transport, and fate of some
pathogens, but they are useful, feasible, and
economical indicators of faecal contamination in
the environment. Under some circumstances, such
as disease outbreaks where it may be important
to identify the source and movement of a specic
pathogen in the environment, it may be useful to
test environmental samples for a specic pathogen of
interest. The investigators should carefully consider
the objectives of the investigation when developing
a sample collection and analysis plan because
testing environmental samples for pathogens can
be challenging and expensive. The investigators
should also consider whether it is necessary to detect
live infectious pathogens or whether it is sucient
† The estimate of low, medium or high impact of sanitation illustrates the potential impact based on the likelihood of continued transmission of the pathogens in conditions of universal
access to safe sanitation systems. A low importance indicates that transmission is likely to persist even when universal access to safe sanitation systems is achieved, as other transmission
pathways are of greater importance.
** or excreted in urine where applicable (S. haematobium)
— no information
1
Taeniasis – adult tapeworm in the intestine
2
Proglottids – worm segment with male/female reproductive organs
Pathogen Health
signicance
Transmission
pathways
Important
animal source
Likely
importance
of
sanitation
for control
†
Concentration
excreted in
faeces**
Duration
of
excretion
Additional
references
Trichuris trichiura
(whipworm)
Largely
asymptomatic. With
heavy infection –
chronic abdominal
pain and diarrhoea,
iron deciency
anaemia, growth
faltering, dysentery
syndrome, recurrent
rectal prolapse.
Via consumption of
contaminated soil and
crops. Hand-to-mouth.
None High up to perhaps
50,000 eggs
While
infection
persists
Bethony et
al., 2006
Table 6.1 Excreta-related pathogens (continued)
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CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
to detect the nucleic acid from the pathogen. Given
the limitations of some pathogen concentration
and detection methods, negative results should be
interpreted with caution.
Unlike testing clinical specimens, where the goal is
to identify the presence of an etiologic agent and
thereby diagnose an infection, the objective of
microbial analyses of environmental samples is to
obtain quantitative information on the concentration
of fecal contamination (by measuring indicator
organisms) or the concentration of pathogens in
the sample. This quantitative data can be used to
evaluate the risk associated with contact or ingestion
of the environmental sample, or to evaluate the
eectiveness of a treatment process for removing or
inactivating specic pathogens.
Interpretation of enumeration data for public health
requires an understanding of the analytical methods
and the strengths and limitations of the dierent
approaches. Each method has been developed to
isolate and identify a specific agent or group of
agents from an environmental sample.
Environmental samples need to be prepared for
microbial analysis, to concentrate the pathogen
target in the sample in order to increase the chances
of detection. The method used for preparation
will depend on the type of sample (e.g. sewage,
sludge, surface water), the expected concentration
of organisms (whether dilution or concentration is
required) and the target organism. Some sample types
(e.g. faecal sludge) present a considerable challenge
for preparation and subsequent enumeration, as
the method may consist of numerous steps, each
of which can provide the opportunity for loss of
the target material (i.e. organisms or nucleic acid).
Analytical methods, therefore, have imperfect
pathogen recovery and, where possible, quantitative
results should be corrected for the method recovery.
Enumeration methods target a specic characteristic
of microorganism, and can be grouped according to
visual identication, cultured-based and molecular-
based methods.
Visual identification is used to count organisms
under the microscope based on characteristic
morphological features (often using specic staining
techniques). Visual identication of microorganisms
in environmental samples is rarely used because
of poor sensitivity and specificity. Experienced
technicians can identify some viruses, protozoan
cysts or oocysts, or helminths eggs and larvae, on
the basis of their morphology and size. However,
microscopic inspection is usually reserved for clinical
specimens. Many pathogenic microorganisms in
environmental samples can not be identied solely
by visual inspection.
Culture-based methods rely on the ability of the
target organism to reproduce under a specic set
of conditions, and colonies (bacteria) or plaques
(viruses) are counted. Culture-based methods only
identify infectious organisms. However, as some
organisms may be viable but non-culturable (i.e. not
able to reproduce in the laboratory, but still infectious
to a human host), these methods may underestimate
the number of viable organisms in the sample.
Molecular-based methods (e.g. [quantitative]
polymerase chain reaction – [q]PCR) are used to
identify the presence [and quantity] of a specific
target sequence of genetic material in the sample.
Molecular methods are used for pathogens that
cannot be cultured (or are dicult to culture) and
are sometimes favoured in comparison with culture
or visual identication owing to their specicity and
sensitivity. PCR detection has been a valuable tool
for environmental microbiology. There are, however,
a number of important drawbacks, including:
• standard PCR techniques cannot distinguish
between viable and dead organisms;
116
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 6
• interpreting quantitative results is challenging
and depends on the number of target sequences
per microorganism (for intracellular pathogens,
complexity is further increased); and
• the specificity of the method for targeting the
organism of interest depends on the selected probe
or primer – the longer the sequence, the more
specic the probe or primer is expected to be.
The result from the analysis may be quantitative (a
number of organisms, colonies or plaques); presence/
absence of the target organism or sequence (which,
when done in a series of parallel samples, can
be reported as a most probable number (MPN)
estimation); or semi-quantitative (such as the output
of a qPCR expressed as number or concentration
of genome copies in the sample). In many cases,
methods for analysis of many human pathogens from
environmental samples (including faeces, sewage,
sludge and surface water) are not yet standardised.
This is an emerging science, with ongoing rapid
developments in methodological approaches.
Important differences may exist in data reported
from dierent laboratories using valid but dierent
approaches for sample preparation and analysis.
Analytical results from environmental samples
should be interpreted in the light of these important
methodological constraints. More information can be
found in Maier, Pepper & Gerba, 2009, and WHO, 2016.
6.3.2 Pathogen occurrence in faecal waste
Some reported human pathogen concentrations
from faeces and sewage are summarised Table 6.2
(adapted from Aw, 2018).
Only infected individuals excrete enteric pathogens.
The concentration of pathogens in faecal waste,
therefore, depends on the prevalence of infection in
the population and the pathogen shedding density
(Hewitt et al., 2011; Petterson, Stenström & Ottoson,
2016), and these factors should be considered
when interpreting the data in Table 6.2 (additional
information can be found in Aw, 2018).
Prevalence of infection: While only infected humans
and animals will excrete enteric pathogens, not all
infections result in symptoms of disease (some people,
in other words, have asymptomatic infections). The
infection rate, rather than the disease rate, will drive
pathogen occurrence in faecal waste. Higher pathogen
concentrations in faecal waste can be expected in
communities with a high endemic disease rate.
Additionally, the concentration of pathogens in
faecal waste from a community increases during an
outbreak. For example, during a large outbreak of
Cryptosporidium hominis infection in Sweden, the
oocyst concentration in the community wastewater
increased from < to 200 oocysts /10 L before the
outbreak to a peak of 270,000 oocysts /10L (Widerström
et al. 2014). Over the course of this outbreak it was
estimated that nearly one third of the population was
infected (27,000 out of around 60,000 inhabitants).
Shedding density: For most pathogens, the
information available on shedding density (i.e. the
concentration of pathogens in the faeces of infected
individuals) is limited to a small number of samples from
symptomatic subjects. It is, therefore, dicult to know
how representative these values are for all infections
(across dierent age groups and settings) with varying
severity of disease. More information is available for
norovirus in comparison to other pathogens, following
a detailed study involving 102 subjects (71 symptomatic
and 31 asymptomatic) to systematically assess the
duration and course of shedding (Teunis et al., 2015).
The study showed a similar shedding pattern between
symptomatic and asymptomatic infections. Virus
concentration rose rapidly to a peak within a few days
from the onset of infection and then gradually declined.
The peak shedding density (determined by molecular
analysis methods) varied from 105 to 109 genome
copies /g faeces, and the total duration of shedding
varied from 8 to 60 days. Six other studies, reviewed
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CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
Table 6.2 Pathogen concentrations in faeces and raw sewage (adapted from Aw, 2018)
Pathogen Concentration /
g in faeces
Concentration /
L in sewage
Notes regarding sewage
data
References
BACTERIA
Campylobacter spp. 6 ×10
6
to 10
9
CFU 10
2
to 10
7
CFU
2.5 ×10
3
to 1.6 ×10
4
MPN
4.1 ×10
6
GC
5 Studies in Europe
and USA
Pitkanen & Hanninen, 2017
Pathogenic members of
E. coli and Shigella spp.
10
6
to 10
8
(Shigella)
10
2
to 10
5
CFU
(pathogenic E. coli in
cattle faeces)
1.5 ×10
3
to 1.4 ×10
7
CFU
(Shigella)
10
2
to 10
4
CFU (Pathogenic
E. coli)
2 studies in South Africa and
Spain
Garcia-Aljaro et al., 2017
Helicobacter pylori No quantitative data 2 ×10
3
to 2.8 ×10
4
GC 1 study in USA Araujo Boira & Hanninen, 2017
VIRUSES
Adenoviruses 10
11
particles 1.7 ×10
2
to 3.3 × 10
9
GC 8 studies in Brazil, Europe,
Japan, USA and New Zealand
Allard & Vantarakis, 2017
Astrovirus 7.6 ×10
2
to
3.6 × 10
15
GC
10
3
to 4.3 ×10
7
GC 5 studies in Brazil, France,
Japan, Singapore and Uruguay
da Silva et al., 2016
Hepatitis A virus >10
6
particles 2.95 ×10
5
to 9.8 × 10
8
GC 5 studies in Brazil and Tunisia van der Poel & Rzezutka, 2017a
Hepatitis E virus 10
5
GC 10
4
GC 2 studies in Norway and
Switzerland
van der Poel & Rzezutka, 2017b
Norovirus and other
caliciviruses
10
11
GC 1.7 ×10
2
to 3.4 × 10
9
GC 18 studies in Europe, Japan,
Uruguay, New Zealand and USA
Katayama & Vinjé, 2017
Polioviruses and other
enteroviruses
10
6
to 10
7
0 to 3.4 ×10
4
(cell culture) 15 studies in Africa, Europe,
Japan, New Zealand and USA
Betancourt & Shulman, 2016
Rotavirus 10
10
to 10
12
particles 2.2 ×10
2
to 2.9 ×10
8
GC 5 studies in Argentina, Brazil,
China and USA
da Silva et al., 2016
PROTOZOA
Cryptosporidium spp. 10
6
to 10
7
oocysts 1.6 ×10
4
oocysts 20 studies in South and North
America, Asia, Europe and
Africa
Nasser, 2016
Cyclospora cayetanensis 10
2
to 10
4
oocysts 1.2 ×10
4
GC Based on a study in USA Chacin-Bonilla, 2017
Entamoeba coli,
Entamoeba histolytica
1256 cysts 1329 to 2834 cysts
893 cysts
17 wastewater treatment
plants in Tunisi
Ben Ayed & Sabbahi, 2017
Giardia duodenalis 56 to 5 ×10
6
cysts 759 cysts
1 to 10
5
cysts
17 wastewater treatment
plants in Tunisia
17 studies in Asia, North and
South America, Europe and
South Africa
Boarato et al., 2016
HELMINTHS
Ascaris spp. 204 eggs 46 eggs
(Maximum: 175)
455 eggs
1 study in Iran (N=60)
17 wastewater treatment
plants in Tunisia
Sossou et al., 2014; Shara et al.,
2015
Liver ukes e.g.
Clonorchis sinensis
2.8 x 10
3
eggs No data Murell & Pozio, 2017
Schistosoma mansoni 53 eggs No data Sossou et al., 2014
Taenia spp. No data 51 eggs 17 wastewater treatment
plants in Tunisia
Ben Ayed et al., 2009
GC: Gene copies; CFU: Colony forming units; MPN: Most Probable Number.
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WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 6
by Katayama & Vinjé (2017), also reported variable
norovirus concentrations in faeces. Ajami et al. (2010),
for example, reported norovirus concentrations in the
faeces of 11 subjects ranging from 3.76 × 10
7
to 1.18 ×
10
13
genome copies/g. Considerable variation could
therefore also be expected for other pathogens, and
the indicative concentrations given in Tables 6.1 and
6.2 are representative of the limited data available. The
natural variability in prevalence and shedding density
mean that the concentration of pathogens in faecal
waste is dicult to generalize, and wide variability both
between locations and over time should be expected.
The volume of water combined with the faecal waste
will also drive the concentration through dilution. In
the case of centralized sewer networks, this water may
include industrial discharges and stormwater as well as
household usage.
6.3.3 Pathogen persistence in the environment
Assessing the survival time of pathogens in the
environment is a key component of health risk
assessment. In order to present a risk to human health,
enteric pathogens must persist in the environment for
long enough to infect a new host. Natural die-o and
inactivation is an important health protection measure.
Individual pathogens vary widely in their environmental
persistence, and environmental conditions are critical.
Generalizations are dicult, and factors inuencing
microbial persistence have been reviewed and
summarised in Table 6.3 (Yates, 2017). Most studies,
however, have been undertaken using indicator
organisms
1
rather than human pathogens, and
often conducted in water (marine, fresh surface, or
groundwater) rather than wastewater; these present
serious limitations to inferences about pathogen
behaviour and survival in human excreta.
Pathogens are, typically, adapted to the conditions of
the human or animal gut and so persistence under
unfavourable conditions is limited. Nevertheless,
dark and cool conditions, neutral pH and sucient
moisture may lead to prolonged survival of
pathogens. Poliovirus type 1 and Hepatitis A virus,
1
These tend to be non-pathogenic microorganisms that are natural inhabitants of the
gastrointestinal tract. They are relatively cheap and easy to enumerate and they are used
to indicate faecal contamination.
Table 6.3 Factors inuencing microbial persistence (from Yates, 2017)
Factor Eect
Temperature Longer persistence at lower temperatures
Microbial activity Variable, depending on microorganism and environmental conditions; generally, more microbial activity results in
shorter persistence in the environment
Dissolved oxygen Variable results have been reported
Organic matter May protect microorganism from inactivation; other studies have shown that the presence of organic matter may
reversibly retard virus infectivity
Microorganism type In general, helminths persist the longest, followed by viruses and protozoa, while bacterial persistence is generally the
lowest
Aggregation Aggregation generally enhances persistence
pH Varies depending on microorganism, but persistence tends to be best at near-neutral pH values; many enteric viruses
are stable over a pH range 3–9
Moisture content Many microorganisms persist longer in soils with higher moisture content
Adsorption to solid
materials
Variable results have been reported. In many cases, adsorption to solid materials increases persistence by providing
protection from predation
Soil properties Eects on persistence are likely related to degree of adsorption to soil
Light Light, especially ultraviolet light from sunlight or articial sources, is germicidal. Exposure to sunlight will reduce the
survival of viruses, bacteria and protozoa in water and soil surfaces
119
CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
for example, remained infectious for more than a
year in mineral water stored at 4°C (Biziagos et al.,
1988). For Cryptosporidium, under dark conditions
for four dierent natural waters, the time for 2 log
10
inactivation (99% reduction) varied between 10 and
18 days at 30°C but increased to more than 200
days at 5 °C in all cases (Ives et al., 2007). In the case
of faecal sludge, a review of the literature (Manser
et al., 2016) clearly demonstrated a temperature-
time relationship for Ascaris eggs during anaerobic
digestion; at a digestion temperature of 50 °C a 2log
10
inactivation of eggs was recorded as between less
than 2 hours up to 4 days, compared to more than
2500 days at 10 °C. Norwalk virus has been detected
for over three years in groundwater held at room
temperature in the dark and the virus remained
infectious for at least 61 days (Seitz et al., 2011);
norovirus outbreaks are often linked to faecal
contamination of groundwater.
When assessing the safety of a sanitation system
or exposure pathway, the specific environmental
conditions and most relevant pathogens need to
be considered. As a minimum, individual pathogen
groups (i.e. bacteria, viruses, protozoa and helminths)
should be addressed separately; however, even within
these groups there can be some important distinctions.
6.3.4 Pathogen infectivity
The probability that a pathogen will be able to
achieve an infection in an exposed individual depends
on both host and pathogen factors. Host factors,
including immune status, nutritional status, age and
the presence of existing infections or diseases, will all
inuence an individual’s susceptibility to infection.
In addition, pathogen-specic factors that can be
related to the specic strain and its virulence will
drive the infectivity.
Table 6.4 Selection of ID50 values from human challenge data
Pathogen ID50 Dose unit Reference
BACTERIA
Camypylobacter 890 CFU Black et al., 1988
E. coli (EIEC) 2,100,000 CFU DuPont et al., 1971
Salmonella typhi 1,100,000 CFU Hornick et al., 1966; 1970
Shigella 1,500 CFU DuPont et al., 1972
Vibrio cholera 240 CFU Hornick et al., 1971
VIRUSES
Adenovirus type 4 1.1 TCID
50
Couch et al., 1966
Echovirus strain 12 920 PFU Schi et al., 1984
Rotavirus 6.2 FFU Ward et al., 1986
Norwalk virus 18–2800 genome equivalent copies Teunis et al., 2008; Atmar et al, 2014
PROTOZOA
Cryptosporidium parvum
a
Iowa
Tamu and
UCP isolates
87
9
1042
oocysts Teunis et al., 2002
Cryptosporidium hominis
a
10 oocysts Chappell et al., 2006
Giardia duodenalis 35 cysts Rendtor, 1954
TCID
50
– tissue culture infectious dose; PFU – plaque forming units; FFU – focus forming units; CFU – colony forming units.
a
From cited references. All other parameters obtained to two signicant gures from QMRAwiki (www.qmrawiki.canr.msu.edu).
120
WHO GUIDELINES ON SANITATION AND HEALTH
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Quantitative information on pathogen infectivity
has been obtained for some pathogens from human
challenge studies. These studies provide observations
of infection and illness rates following exposure to
a known pathogen dose; they do, however, have
limitations to their applicability and generalizability
as they are typically conducted in healthy adult males
using a single strain of a particular pathogen. Table
6.4 provides an overview of some ID50 values (dose
at which 50% of subjects would become infected;
or probability of infection = 0.5) from human
challenge studies (based largely on the QMRAwiki –
www.qmrawiki.canr.msu.edu). No human challenge
data are available for any parasitic worms. Many
studies have been published on norovirus infectivity
based on molecular data (reviewed by van Abel et al.,
2017); infectivity is high for individuals susceptible
to infection, but interpreting the required dose from
molecular data is challenging.
6.4 Treatment and control
Wastewater and sludge treatment processes are an
essential barrier for protection of human health. These
systems, however, are often designed to achieve
environmental goals or aesthetic objectives, rather
than specic pathogen reduction targets, and some
treatment processes have been shown to have a
relatively minimal impact on pathogen levels in
sewage (with less than 90% reduction of any of the
four pathogen groups). When microbial reductions
are explicitly considered, they often rely on bacterial
indicators (e.g. E. coli or enterococci) with little
consideration of the other pathogen groups.
To ensure that pathogen reduction objectives are
achieved, the mechanism of pathogen inactivation
needs to be dened and the critical limits of those
mechanisms identied for the key pathogens of interest.
Common pathogen inactivation mechanisms include:
• Time: Natural inactivation over time is a valuable
treatment mechanism incorporated into many
systems. The time needed to achieve inactivation
will depend on temperature and specic conditions
(see Section 6.3.3). Critical limits relate to ensuring
that the minimum solid/hydraulic residence time
has been achieved.
• Sedimentation and partitioning to solids:
Sedimentation processes are typically designed for
suspended solids removal; pathogens, however,
often attach to particulates in wastewater and
can be removed simultaneously. It is, thus,
relevant to know the extent to which dierent
pathogens adsorb to the particulate matrix to
estimate removal capacity. In waste stabilisation
ponds, allowing time for sedimentation can lead
to removal of larger pathogens (particularly
helminths).
• Solar radiation: Many pathogens, particularly
viruses, are susceptible to inactivation by solar
radiation. The extent of removal will be driven by
water depth, clarity and exposure time.
• Thermal treatment: When storage is combined
with a thermal process (either naturally through
composted waste or by the addition of heat)
pathogen reduction times can be drastically
reduced (see Section 6.3.3). To ensure that these
reductions have been achieved, it is necessary
to know the temperature profile of the waste
and to ensure that the required temperature was
achieved for adequate duration.
• Filtration: Physical ltration processes from natural
wetlands to filter beds can effectively remove
pathogens. Removal depends upon the lter pore
size (with smaller organisms – i.e. viruses – more
dicult to remove) and the biological activity of
the lter matrix. An established biolm within the
lter will enhance removal and predation of all
pathogen groups.
• Chemical disinfection: Addition of chemical
disinfectants will enhance pathogen reduction.
The response, however, will be pathogen-specic
and depend on the dose, water matrix and, most
notably, the organic content. In situ disinfection
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CHAPTER 6. EXCRETA-RELATED PATHOGENS
Chapter 6
using lime to raise the pH has been shown to be a
useful strategy in emergency settings (Sozzi et al.,
2015).
• Attenuation in the subsurface: Many sanitation
technologies rely on pathogen attenuation
(physical removal by ltration, adsorption to soil
and inactivation) in the subsurface. The fate of
pathogens in the subsurface is determined by their
survival in soils and retention by soil particles and
is mainly determined by local climatic conditions
(in particular temperature, sunlight and rainfall),
the nature of the soil (e.g. particle size, cation
exchange capacity and composition) and features
of the microorganism (e.g. size and shape). The
capacity of the soil to remove organisms increases
with a decrease in soil-water content. Laboratory
and field experiments have shown that many
soils have a high retention capacity for bacteria
and viruses (Drewey & Eliassen, 1968; Gerba et al.,
1975; Burge & Enkiri, 1978). In general, retention of
bacteria and viruses increases with an increase in
clay content, cation exchange capacity of the soil
and specic surface area (Marshall, 1971; Burge &
Enkiri, 1978).
A wide range of treatment approaches and
technologies are presented in Chapter 3. While a
general indication of pathogen reduction ecacy
is provided in that chapter, it is emphasized that
site specific evaluation of the relevant pathogen
removal mechanisms (under both expected and
event conditions) is needed to assess the actual
reduction ecacy and hence safety of each treatment
barrier. This reduction efficacy must be assessed
for each of the key pathogen groups, and with
particular attention to any reference pathogens of
local signicance.
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CHAPTER 7. METHODS
Chapter 7
7.1 Introduction
These guidelines were developed according to the
procedures and methods described in the WHO
handbook for guideline development (WHO 2014).
The development process included formulating
scoping questions, prioritising key questions,
conducting systematic reviews to answer the key
questions, assessing the quality of the evidence,
formulating recommendations, writing the guidelines
and developing a plan for their dissemination and
implementation. The proposal for these guidelines was
approved by the WHO Guidelines Review Committee
(GRC) in November 2015. The guidelines were reviewed
by the Chair and Secretariat of the WHO Guidelines
Review Committee but did not have to undergo formal
review by the Guidelines Review Committee, as the
recommendations provided are largely considered
so-called good practice statements. Good practice
statements account for “situations, in which a large
body of indirect evidence, made up of linked evidence
including several indirect comparisons, strongly supports
the net benet of the recommended action”; they are
considered “actionable, necessary and of both large
and unequivocal benet” (Guyatt et al., 2016).
This chapter details the methods used in the
development of the guidelines.
7.2 Contributors
Contributions to the guidelines development process
were made by a number of groups and individuals
(including end-users and technical experts from a
wide range of disciplines). The groups are outlined
below and members of the dierent groups are listed
in the acknowledgements.
7.2.1 WHO steering group
The WHO steering group comprised WHO sta from
the Department of Public Health, Environmental and
Social Determinants of Health (PHE), the Department
for Neglected Tropical Diseases, and the Department
for Pandemic and Epidemic Diseases as well as
environmental health regional focal points from all six
WHO regions. The steering group was involved in the
planning, coordination and management of the whole
process from the development of scoping questions
(see Section 7.3) to nal publication of the guidelines.
7.2.2 Guidelines development group
The Guidelines Development Group (GDG) included
30 members with expertise across the various relevant
content areas. It was consulted at critical points during
the development process, including commenting on
the key questions and suggested methods for the
systematic reviews, contributing to and/or reviewing
systematic reviews, formulating recommendations
and supporting the drafting and reviewing of dierent
chapters of the guidelines. The group was balanced in
terms of gender and geography, and included technical
experts as well as end-users. The GDG also included
a methodologist with experience in systematic
reviews, the GRADE (Grading of Recommendations,
Assessment, Development and Evaluation) approach
and translation of evidence into recommendations.
Chapter 7
METHODS
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7.2.3 Systematic review teams
The commissioned systematic reviews were
conducted by experts with extensive experience in
carrying out systematic reviews on environmental
health interventions (including water, sanitation and
hygiene) using Cochrane-style as well as broader
qualitative and mixed-method systematic review
methods and application of the GRADE approach for
assessing the quality of the evidence.
7.2.4 External peer review group
The external peer review group provided input towards
the systematic reviews and appraised and commented
on advanced draft chapters of the guidelines.
7.2.5 External partners and observers
Representatives of external partners were invited to
participate as observers in the meetings of the GDG.
7.2.6 Management of conflicts of interest
All members of the GDG and external peer review
group completed WHO declaration of interest forms.
These were then reviewed for potential conflicts
of interest. While several conicts of interests were
declared, none of these required any member of the
GDG or external peer review group to be excluded
from their role.
7.3 Scoping and question
formulation
Sanitation, as addressed in these guidelines, is
concerned with the complete sanitation service
chain, from toilet capture and containment through
emptying, transport, treatment (in-situ or o-site) and
nal disposal or reuse (Figure 1.2).
Interventions to ensure adequate sanitation include
both technologies (which could be sanitation
facilities [e.g. toilets], services [e.g. safe faecal sludge
removal] or systems [e.g. wastewater treatment])
and behavioural change activities. Sanitation
interventions often comprise multiple components,
which may act independently or interdependently;
the components describe the “what?” of the
intervention, including aspects of timing (when),
dose (how long) and intensity (how often) (Rohwer
et al. 2017). Implementation of the intervention or of
specic components may involve policies, regulations
and provision of nancial incentives or resources
(including personnel). Implementation has been
defined as an actively planned and deliberately
initiated eort with the intention to bring a given
intervention into policy and practice within a
particular setting (Pfadenhauer et al., 2017).
The scoping questions and key questions for the
guidelines were informed by critical current evidence
needs in sanitation and developed through a number
of processes, namely:
• initial discussions among the WHO steering group
with selected members of the GDG;
• a survey of selected global sanitation actors
within health, public works, sanitation nancing,
academic institutions, international organizations,
development banks and NGOs; and
• consultation with all members of the GDG during
the rst GDG meeting.
The prioritised key questions were subsequently re-
formulated according to the ‘PICO’ format (population
– intervention – comparison – outcome) to focus
and improve the scientic rigour of the subsequent
systematic reviews. The ve key questions fall into two
areas, namely implementation-focused (question 1)
and intervention-focused (questions 2–5).
Implementation focused
• How do contextual factors (e.g. population, setting,
climate) and implementation aspects (e.g. policies,
regulations, roles of the health and other sectors,
management at different levels of government)
inuence access to as well as uptake and use of
dierent interventions?
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CHAPTER 7. METHODS
Chapter 7
Intervention focused
• How eective are dierent sanitation interventions
in achieving and sustaining access to, uptake and
use of sanitation?
• How eective are dierent sanitation interventions
in reducing environmental faecal load?
• How eective are dierent sanitation interventions
in reducing exposure to faecal pathogens?
• How eective are dierent sanitation interventions
in improving specic health outcomes (including
infectious diseases, nutritional status, well-being
and educational outcomes)?
These questions are presented within the conceptual
framework in Figure 7.1, which illustrates the
pathways through which the intervention and its
implementation are thought to influence health
via multiple intermediate outcomes. An important
intermediate outcome is access to, as well as short-
term uptake and long-term, sustained use of dierent
sanitation interventions, be they technologies or
behaviours. These are assumed to inuence both the
faecal load in the environment and human exposure
to faecal contamination. Ultimately, greater access
to and use of sanitation interventions and a reduced
faecal load are expected to lead to improved health
outcomes (i.e. infectious disease and nutritional
outcomes) as well as educational outcomes and
mental health and social well-being. The conceptual
framework also reects the fact that contextual factors
can inuence both the way in which an intervention is
implemented and the way in which it operates to aect
IMPLEMENTATION
(policy and regulation, nance, organization)
CONTEXT
(geographical, epidemiological, socio-economic,
socio-cultural, political, legal, ethical)
HEALTH IMPACT
Infectious
Faecal-oral infections
Helminth infections
Insect vector diseases
Sequelae
Stunting and consequences of stunting
Impaired cognitive function
Pneumonia
Anaemia
Wellbeing (immediate and long term)
Anxiety, School absence, Poverty
Decreased economic productivity,
Sexual assault, Adverse birth outcomes,
Anti-microbial resistance
Access
Use and sustained use
Faecal load in the environment
Human exposure
Fluids
Flies
Soil/
surfaces
Faeces
Food
New host
SANITATION INTERVENTION
(behaviour, technology)
Fingers
Figure 7.1 Conceptual framework for guidelines development
128
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 7
health. These contextual factors are less amenable to
change and may explain some of the dierences seen
in intervention eectiveness between geographical
settings and countries.
7.4 Evidence retrieval, assessment
and synthesis
The key questions were used to dene the required
systematic reviews, a core component to inform
the formulation of recommendations. The specic
research questions derived from the key questions
and the conceptual framework are shown in Table
7.1. Examination of the literature revealed that
recent independently conducted reviews existed
in a number of areas (Yates et al., 2015; Hulland et
al., 2015; Speich et al., 2016; De Buck et al., 2017;
Majorin et al., 2018; Ejemot-Nwadiaro et al., 2015;
Venkataramanan et al., 2018). Other systematic
reviews were specifically commissioned (and
published or submitted for publication in the peer-
reviewed literature) to cover the remaining areas. The
commissioned reviews were all conducted largely in
accordance with Cochrane standards (Doyle, 2016)
and were based on an a priori protocol. The reviews
employed systematic search strategies across a large
number of relevant major electronic and, where
appropriate, grey literature databases, and sought
to identify published as well as unpublished studies.
Searches were conducted in English but, depending
on the review, eligible studies published in several
other languages, including Spanish, Portuguese,
French, German or Italian, were also included. The
systematic reviews developed and applied clearly
dened inclusion/exclusion criteria, usually through
two independent assessors, extracted data onto
pre-specied data extraction forms and assessed
the quality of the included studies using a t for
purpose risk of bias or quality appraisal tool, such
as the Liverpool Quality Appraisal Tool (Pope et al.,
personal communication). Heterogeneity across
included studies was explored and described and,
depending on the nature of the systematic review,
evidence synthesis was undertaken using meta-
analysis (including pre-specied subgroup analyses),
tabular or narrative synthesis or a form of qualitative
evidence synthesis.
Methodological details for each of the reviews,
including search strategy, eligible interventions,
outcomes and study designs, as well as risk of
bias assessment or quality appraisal and evidence
synthesis, are available in the published reviews (see
Table 8.1 and references therein).
7.5 Evidence grading
7.5.1 Grading evidence of effectiveness
The GRADE (Grading of Recommendations Assessment,
Development and Evaluation) approach (Guyatt et al.,
2008; Schünemann et al., 2008) was used to rate the
quality of the reviewed evidence. In GRADE, quality of
evidence reects the certainty that the true eect of an
intervention lies on one side of a specied threshold,
or within a chosen range (Hulcrantz et al., 2017). In
applying GRADE in the guidelines, we were particularly
interested in whether the true eect of an intervention
would be dierent from the null, i.e. in knowing whether
the intervention shows any eect versus no eect.
In GRADE, the quality of a body of evidence for a given
outcome is assessed, initially, based on the design of
the underlying studies (where randomized controlled
trials start off as high quality and all other study
designs start o as low quality). Consideration of
additional factors (shown below) may either decrease
(ve factors) or increase (three factors) the overall
quality of evidence (irrespective of study design).
Factors to decrease the quality of evidence:
• Risk of bias: The condence in an eect decreases if
studies suer from major limitations that are likely to
result in a biased assessment of the intervention eect.
• Indirectness of evidence: The confidence in
an effect may decrease if there are important
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CHAPTER 7. METHODS
Chapter 7
dierences between the PICO of interest and the
PICO examined in the available studies (e.g. if the
population of interest are children, but all available
studies included only adults, or if only surrogate
outcomes are reported).
• Unexplained heterogeneity or inconsistency of
results: The condence in an eect may decrease
when studies yield widely diering estimates of
eect, and when no plausible explanation for this
heterogeneity can be identied.
• Imprecision of results: The confidence in an
eect may decrease when results are imprecise,
i.e. when condence intervals of reported eect
estimates are wide and include both the possibility
of a relevant eect (dened by the pre-specied
threshold or range) and the possibility of no such
effect, or when the number of participants or
events is small.
• High probability of publication bias: The
condence in an eect may decrease when we
have reason to assume that relevant studies have
been conducted but not published. Indicators
of publication bias include asymmetric funnel
plots, or a large share of small, industry-sponsored
studies.
In considering each of these factors in turn, the quality
of evidence can be rated down by -1 (if there are serious
concerns with the given factor) or rated down by -2 (if
there are very serious concerns with the given factor).
Factors to increase the quality of evidence:
• Magnitude of eect: When methodologically well-
done observational studies yield large estimates of
the magnitude of an eect, one may be particularly
condent in the results. The threshold will depend
on the review question and the wider context, but it
has been suggested that for dichotomous outcomes,
a risk ratio (RR) > 2 or a RR < 0.2 may indicate a
large eect. For public health interventions lower
thresholds may be justied.
• Residual confounding: On occasion, all plausible
biases from studies may be working to
underestimate an apparent intervention eect,
or suggest a spurious eect when results show no
eect.
• Dose-response gradient: When larger doses, or
more intensive interventions show larger eects
this may increase our condence in the results.
Quality of evidence can be increased by +1 for all residual
confounding operating to underestimate an eect and
the presence of a dose-response gradient, and by +1 or
+2 for a large or very large eect respectively.
On the basis of this approach the review evidence was
rated as one of the following four levels:
• High quality: This research provides a very good
indication of the likely eect. The likelihood that
the eect will be substantially dierent is low.
• Moderate quality: This research provides a good
indication of the likely eect. The likelihood that the
eect will be substantially dierent is moderate.
• Low quality: This research provides some indication
of the likely eect. However, the likelihood that it
will be substantially dierent is high.
• Very low quality: This research does not provide a
reliable indication of the likely eect. The likelihood
that the eect will be substantially dierent is very
high.
For each of the commissioned systematic reviews a
summary of ndings table was created, which outlines
the reasoning behind a given quality of evidence rating
(see Table 8.1 and references therein).
7.5.2 Examining the conceptual framework
While the GRADE approach provides a useful
framework for assessing the quality of evidence
in relation to individual outcomes, it is less
suited to a comprehensive assessment of all the
types of evidence needed in relation to complex
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Chapter 7
interventions (Rehfuess & Akl, 2013; Montgomery
et al.), including those within the sanitation area.
Sanitation interventions are complex interventions
as they involve multiple components, inuence a
broad range of health (and non-health) outcomes,
are delivered through and inuenced by multiple
stakeholders and are inuenced by many contextual
factors, including socio-economic, socio-cultural and
geographical aspects (Rehfuess & Bartram, 2014).
To account for the complex nature of sanitation
interventions, the evidence was also reviewed from
a whole system perspective (illustrated in Figure 7.1).
This allowed for:
• the exploration of which links are well-supported
(versus less well-supported) by evidence (identifying
potential research needs);
• an assessment of the coherence of the insights
provided across the system, drawing on information
from other disciplines (including microbiology and
engineering); and
• the exploration of which links in the pathways
may be responsible when a given intervention (or
package of interventions) has failed to demonstrate a
positive health impact; e.g. poor intervention design
(‘intervention failure’ indicated by poor engineering)
versus poor implementation (‘implementation failure’
indicated by low rates of access to and/or use).
7.6 Evidence-to-Decision (EtD)
framework
Several WHO guidelines to date have followed the
GRADE EtD frameworks (Alonso-Coello et al., 2016) to
formulate recommendations and to assess the strength
(strong or moderate) of these recommendations. These
guidelines applied the WHO-INTEGRATE framework, an
EtD framework that is rooted in the norms and values
of the WHO, as agreed upon by all WHO Member States,
and reective of the changing global health landscape.
Importantly, this framework is considered particularly
suitable for complex multi-sectoral population- and
system-level interventions (Rehfuess et al., in press).
The WHO-INTEGRATE framework comprises six
substantive criteria – balance of health benets and
harms, human rights and socio-cultural acceptability,
health equity, equality and non-discrimination, societal
implications, nancial and economic considerations
and feasibility and health system considerations – and
the meta-criterion quality of evidence. It is intended
to facilitate a structured process of reection and
discussion in a problem- and context-specic manner.
For these guidelines, the six substantive criteria were
considered at the end of the guideline development
process and applied across recommendation areas
1, 2 and 3 combined, conceptualizing technical and
behavioural interventions along the entire sanitation
service chain and as part of locally delivered services
as a single multi-component intervention. The
application of these criteria at the level of single
recommendations or even at the level of distinct
recommendation areas would have resulted in much
repetition. Recommendation area 4 is very dierent in
nature: as it does not relate to a specic intervention
but rather describes how the health sector can and
should play an active role in promoting sanitation,
a structured EtD framework was not considered to
be applicable. Notably, the meta-criterion quality
of evidence, while available and applied in relation
to intervention eectiveness (see Chapter 8), was
not applied to the other substantive criteria, mostly
because suitable methods to do so still need to be
developed.
The WHO-INTEGRATE framework template in Table 7.1
was initially lled in by members of the WHO Steering
Group and then reviewed by the full GDG group.
For each criterion, the evidence (where available)
or rationale for making a judgement about how the
criterion would influence the formulation and/or
strength of a recommendation was summarized to
allow for transparent decision-making.
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CHAPTER 7. METHODS
Chapter 7
Criteria Sub-criteria Guiding question Rationale and
evidence
Judgement
Balance of
health benefits
and harms
• Ecacy or eectiveness on health of
individuals
• Eectiveness or impact on health of population
• Patients’/beneciaries’ values in relation to
health outcomes
• Safety-risk-prole of intervention
• Broader positive or negative health-related
impacts
Does the balance between
desirable and undesirable
health eects favour the
intervention or “business as
usual”?
Favours “business as usual”
Probably favours “business
as usual”
Does not favour either the
intervention or “business as
usual”
Probably favours the
intervention
Favours the intervention
Human
rights and
socio-cultural
acceptability
• Accordance with universal human rights
standards
Is the intervention in
accordance with universal
human rights standards
and principles?
No
Probably not
Uncertain
Probably yes
Yes
• Socio-cultural acceptability of intervention by
patients/ beneciaries and those implementing
the intervention
• Socio-cultural acceptability of intervention
by the public and other relevant stakeholder
groups
• Impact on autonomy of concerned stakeholders
• Intrusiveness of intervention
Is the intervention
acceptable to key
stakeholders?
No
Probably not
Uncertain
Probably yes
Yes
Health equity,
equality
and non-
discrimination
• Impact on health equality and/or health equity
• Distribution of benets and harms of
intervention
• Aordability of intervention
• Accessibility of intervention
• Severity and/or rarity of the condition
• Lack of a suitable alternative
What would be the impact
of the intervention on
health equity, equality and
non-discrimination?
Increased
Probably increased
Neither increased nor
decreased
Probably reduced
Reduced
Societal
implications
• Social impact
• Environmental impact
Does the balance between
desirable and undesirable
societal implications
favour the intervention or
“business as usual”?
Favours “business as usual”
Probably favours “business
as usual”
Does not favour either the
intervention or “business as
usual”
Probably favours the
intervention
Favours the intervention
Financial and
economic
considerations
• Financial impact
• Impact on economy
• Ratio of costs and benets
What would be the impact
of the intervention on
nancial and economic
considerations?
Negative
Probably negative
Neither negative
nor positive
Probably positive
Positive
Feasibility and
health system
considerations
• Legislation
• Leadership and governance
• Interaction with and impact on health system
• Need for, usage of and impact on health
workforce and human resources
• Need for, usage of and impact on infrastructure
Is the intervention feasible
to implement?
No
Probably not
Uncertain
Probably yes
Yes
Table 7.1 Evidence to recommendation table using the WHO-INTEGRATE framework (Rehfuess et al.)
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Chapter 7
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R, Akl EA, Davoli M et al. (2016). GRADE Evidence to Decisions (EtD)
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JA (2015). Hand washing promotion for preventing diarrhoea.
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Guyatt GH, Alonso-Coello P, Schünemann HJ, Djulbegovic B,
Nothacker M, Lange S, Hassan Murad M, Akl EA (2016). Guideline
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Rehfuess EA, Bartram J (2014). Beyond direct impact: evidence
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Chapter 8
8.1 Introduction
This Chapter summarizes the systematic reviews for the
key questions outlined in Chapter 7. Examination of the
literature revealed that recent independently conducted
reviews existed in a number of areas (Ejemot-Nwardiario
et al., 2015; Hulland et al., 2015; Yates et al., 2015; Speich
et al., 2016; De Buck et al., 2017; Majorin et al., 2018;
Venkataramanan et al., 2018). Where no existing review
was found, or where those identied did not include
an assessment of the quality of the overall body of
evidence and/or additional rigorous trials had been
published post-review, additional systematic reviews
were specially commissioned (Williams & Overbo, 2015;
Overbo et al., 2016; Sclar et al., 2016; Freeman et al.,
2017; Garn et al., 2017; Sclar et al., 2017, 2018). Table
8.1, at the end of the chapter, provides an overview of
the scope and conduct of each of these reviews, as well
as information on the quality of the included body of
evidence (where available).
8.2 Summary and discussion
of evidence
The evidence suggests that safe sanitation is
associated with improvements in health, including
positive impacts on infectious diseases, nutrition
and well-being. For some health outcomes, both
the magnitude of the observed effects and the
quality of the evidence is low. This is common for
environmental health research generally due to
the paucity of randomized controlled trials and the
inability to blind most environmental interventions.
The evidence is also characterized by considerable
heterogeneity, with some studies showing little or
no eect on health outcomes. Heterogeneity can be
expected in results from studies where, as here, there
was high levels of variability in the settings, baseline
conditions, types of interventions, levels of coverage
and use obtained, study methods and other factors
likely to impact eect sizes. Sub-optimal eects can
also be expected from shortcomings in how sanitation
interventions are implemented (i.e. problems with
delivery of sanitation interventions, sometimes even
leading to implementation failure). These diculties
are compounded by the multiple and highly context-
specic sanitation-related exposure pathways, making
extrapolation from studies problematic.
The overall quality of the evidence as per GRADE
criteria was often rated as low or very low, which is
common for complex interventions like sanitation
(Rehfuess & Akl, 2013; Movsisyan, Melendez-Torres &
Montgomery, 2016a, b). This can be explained partly
by the fact that many studies are observational rather
than experimental, and there is high heterogeneity in
Chapter 8
EVIDENCE ON THE
EFFECTIVENESS AND
IMPLEMENTATION OF
SANITATION INTERVENTIONS
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WHO GUIDELINES ON SANITATION AND HEALTH
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the results. The reviews have highlighted important
limitations common among multiple studies of
sanitation, including:
• lack of details on interventions and implementation
quality, settings and ambient conditions; and
• dierent case denitions, methods of assessment,
frequency and length of follow up, method of
delivery, denitions and methods of assessment of
coverage and use, and pathogens circulating in a
given setting.
Few intervention studies have been conducted to
examine the impact of sanitation interventions, and
those conducted suer from challenges related to
the nature of the evaluation such as lack of blinding,
uncertain generalizability and methodological
challenges (such as reliance on reported outcomes
and susceptibility to bias). Because the contexts of
sanitation interventions vary substantially, the external
validity of individual trials may also be limited.
Importantly, many studies reviewed lack detailed
information on the implementation of the
intervention, in terms of whether it was delivered
as intended, and whether it resulted in intermediate
eects such as reaching intended sanitation coverage
levels and achieving uptake and use of sanitation
services. The absence of such intervention-specic
information makes it dicult to conclude whether
the intervention itself was unlikely to deliver the
desired health impact, or whether failures in delivery
or evaluation methods are at fault.
Finally, the studies reviewed mostly represent LMIC
settings; few studies review the impact of sanitation
interventions in higher income contexts. Gaps in the
evidence and related research needs are detailed in
Chapter 9.
8.3 Reviews of intervention
eectiveness
8.3.1 Access, uptake and use
How eective are dierent interventions in achieving
and sustaining access to, uptake, and use of sanitation?
Four reviews (Garn et al., 2017; Hulland et al., 2015;
De Buck et al., 2017; Venkataramanan et al., 2018)
examined intervention effectiveness in relation to
coverage and use. These reviews evaluated:
• what types of interventions are the most eective
at increasing toilet access and/or toilet use (Garn
et al., 2017);
• what structural and design characteristics are
associated with increased toilet use (Garn et al.,
2017);
• how well interventions to improve adoption of clean
water and sanitation work and the characteristics of
successful interventions (Hulland et al., 2015);
• how eective dierent approaches for promoting
handwashing and sanitation behaviour change are
and the factors that inuence their implementation
(De Buck et al., 2017);
• quality of evidence, impacts and factors aecting the
implementation and eectiveness of community-
led total sanitation (Venkataramanan et al., 2018).
Access and use
In their WHO-commissioned systematic review, Garn
et al. (2017) identied 40 eligible studies (randomized
controlled trials – RCTs; non-randomized controlled
trials and controlled or non-controlled before-and-
after studies), which assessed intervention impacts
on toilet coverage and/or use. Of these, 36 studied
household interventions and four were school-based
interventions. The interventions included increased
access to sanitation facilities or other hardware
(e.g. household toilet, sewer connections), subsidy
provision, education and the promotion of specic
practices (e.g. discouraging open defecation).
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CHAPTER 8. EVIDENCE ON THE EFFECTIVENESS AND IMPLEMENTATION OF SANITATION INTERVENTIONS
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Analysis of the household studies showed that,
overall, the interventions led to a 14% increase in
toilet coverage (95% CI: 10-18%; n=27) compared to
the control groups and a 13% increase in toilet use
(95% CI: 5-21%; n=10). There was heterogeneity in the
results across the dierent sanitation interventions.
The school-based studies were shown to result in
a reduction in the number of pupils per toilet, but
the change in usage could not be calculated due to
inconsistent reporting. Importantly, the impact of
interventions on toilet coverage depended upon the
baseline prevalence; i.e. the communities with the
largest coverage gains often had the lowest baseline
coverage levels. The authors suggest that the gures
on toilet use should be interpreted with caution as
use was dened in dierent ways across the studies
and often relied on self-reported data.
Garn et al. (2017) also reviewed the various structural
and design characteristics associated with using or
not using a toilet. A total of 24 household- or school-
based studies assessing the associations between
sanitation structure and design characteristics and
toilet use were included. Most of these studies were
observational or qualitative. They suggested that
accessibility, privacy, access to hygiene amenities,
toilet maintenance, toilet type and newer toilets were
all associated with increased usage.
Sustained use
In their mixed methods systematic review of the
sustained use of water, sanitation and hygiene
interventions in LMICs, Hulland et al. (2015) identied
59 eligible sanitation-related studies. All study
methodologies were eligible for review and identied
studies included RCTs, observational studies, cross-
sectional surveys, process evaluations, progress
reports and multi-site trials. Most of the studies
related to toilet construction, with some interventions
providing material for toilet construction (either free-
of-charge (n=10), or by selling to the community
(n=17)), provision of toilet construction training (n=20),
community traditional toilet construction (n=9) or toilet
construction by a private company or contractor (n=5).
Twelve of the studies did not describe a sanitation
technology. The literature did not have a common
denition of sustained use/adoption but was dened,
by the authors for the purposes of the review, as the
continued practice of a behaviour or continued use of
a technology for at least six months after the end of the
project period. An in-depth analysis was conducted
on the studies that explicitly reported on sustained
adoption (16 sanitation studies), which included
measurements obtained through self-report, observed
practice, functionality and recalled knowledge. The
behavioural factors, identied in inuencing sustained
adoption, were split into psychosocial, contextual and
technology factors.
Individual psychosocial factors (e.g. perceived benet
and self-ecacy) strongly dominate the literature on
sustained adoption. Interpersonal factors (e.g. social
norms) were also reported to strongly influence
people’s continued practice of behaviours.
The overall context and social norms also have an
impact on uptake and sustained use: for toilet use and
handwashing practice, for example, age and gender
were shown to be strong determinants of a person’s
continued practice – individuals may be barred from
using toilets or unable to practice handwashing
if they are too young, or restricted (culturally or
physically) from accessing facilities.
Finally, cost and durability were the most important
technology-related factors. In low-income settings,
the cost of toilet building was the major factor related
to technology adoption.
Behaviour change
A total of 42 quantitative studies (RCTs, quasi-RCTs,
quasi-experimental and observational designs) and
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28 qualitative studies were eligible for inclusion in
the mixed methods systematic review of behaviour
change approaches for water, sanitation and hygiene
in LMICs (De Buck et al., 2017). The majority of studies
were conducted in rural settings (69% of quantitative
and 68% of qualitative studies) and were conducted
in South Asia or sub-Saharan Africa.
The studies were grouped into the following categories:
• community-based approaches;
• social marketing approaches;
• sanitation and hygiene messaging; and
• approaches based on psychosocial and social
theory.
The review found apparent dierences in the short-
and long-term sustainability of changes in sanitation
behaviours across the four approaches described,
although the evidence for the sanitation outcomes
was categorized as low to very low quality.
The review suggested that while messaging and
awareness raising approaches may result in short
term improvements in handwashing with soap,
the changes are unlikely to be sustained over time.
Further, these approaches seemed to have no eect
on open defecation. No specic conclusions about the
eectiveness of message-based approaches on toilet
use were provided due to either the limited evidence
(single studies) or the very low quality of evidence.
Community-based approaches to sanitation are
among the most widely studied behaviour change
approaches. Results have been varied, but the review
suggests that community-based approaches may be
eective at reducing open defecation and fostering
sustained safe faeces disposal practices.
Robust data on the eectiveness of social marketing
approaches are particularly scarce. Approaches based
on psychological and social theory are generally
viewed as useful but, given the recent nature of these
theory-based approaches, there are only limited
studies upon which conclusions can be based.
Community-led total sanitation (CLTS)
In a mixed-methods systematic review of community-
led total sanitation (CLTS), Venkataramanan et al.
(2018) identified 14 quantitative evaluations,
29 qualitative studies, and 157 case studies from
journal-published and grey literature. Given the
popularity of this rural sanitation behaviour-change
approach, the authors aimed to assess evidence
quality, summarize CLTS impacts and identify factors
affecting implementation and effectiveness. The
review found that evidence available to practitioners
and policymakers is of variable quality, particularly
regarding the ability to estimate the impact of CLTS
on sanitation, health or other community outcomes.
Journal-published literature was generally of higher
quality than grey literature. Over 25% of the literature
overstated conclusions, attributing outcomes and
impacts to interventions without an appropriate
study design, or by making claims about impact using
unveried data sources or anecdotes.
Regarding CLTS impacts, latrine ownership, use and
quality indicators were identified in most of the
literature, but diverse measures were used. Of the
14 quantitative evaluations included in the review,
a statistically signicant increase was reported in
private or shared latrine construction in intervention
groups compared to comparison groups. Declaration
or certication of open defecation-free status was the
second most common indicator, but no consistent
definition was reported. A quarter of the studies
also reported some anecdotal measure of change
in health status in communities after CLTS, while
nine quantitative evaluations measured self-reported
changes in diarrhoea prevalence or anthropometric
measures in children. Overall, there was limited
evidence indicating whether or not there had been
sustained sanitation behaviour change or health
impacts as a result of CLTS.
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A qualitative content analysis of the literature
identied implementation and community-related
factors reported to affect implementation and
eectiveness of CLTS. Of the 21 implementation-
related factors, the most cited were:
• government awareness and buy-in for CLTS;
• local government ownership;
• institutional capacity; and
• quality of triggering activities.
Of the 22 community-related factors, the most
frequently reported were:
• community participation;
• access to supply, nancial resources and technical
support;
• climate conditions; and
• expectation of latrine subsidies.
Overall, however, there was minimal systematic
research of the CLTS implementation process and its
adaptations.
8.3.2 Environmental faecal load reduction
How eective are dierent sanitation interventions in
reducing environmental faecal load?
In an exploratory review of the literature, Williams &
Overbo (2015) examined studies on the pathways
and extent of unsafe return of human excreta to the
environment along the sanitation service chain for
pit latrines, septic tanks and sewerage. The review
focused on leakage of faecal sludge, of the liquid
waste fractions from septic tanks and latrines and
of sewered wastewater. Numerous studies showed
that many of the sanitation systems currently in
use do not adequately prevent the unsafe return of
excreta to the environment. Several studies showed,
for example, that unlined pits and damaged facilities
do not provide eective containment and can cause
contamination of the household and surrounding
area. In some cases, pit latrines may be badly aected
by storms, rainfall and oods. Latrine pits and septic
tanks are often not emptied and the liquid fraction
may be discharged with little treatment to open
drains or open ground or groundwater sources.
Where pits are reportedly emptied there was very
little information on the fate of the collected sludge;
this may be dumped or used in agriculture instead
of being delivered to treatment. Few countries
have dedicated treatment facilities for faecal sludge
or wastewater treatment plants designed for co-
treatment of faecal sludge. Sewer connections, alone,
were not sucient to ensure adequate separation
of faecal waste from people, as misconnections and
exltration, broken pumping stations and combined
sewer overows are common. Poor performance of
wastewater treatment plants due to overloading,
poor operation and maintenance and unpermitted
industrial loads means wastewater may be discharged
untreated or only partially treated.
8.3.3 Exposure to faecal pathogens
How eective are dierent sanitation interventions in
reducing exposure to faecal pathogens?
Sclar et al. (2016) reviewed the literature assessing
the direct impact of sanitation on the pathways
of faecal exposure. A total of 29 eligible studies
were identied, of which 23 examined transmission
pathways (eight RCTs, one non RCT, one quasi RCT,
11 cross-sectional studies, one case control study
and one cohort study) following improved sanitation
measures, and six (all cross-sectional studies) assessed
drinking-water supply contamination on the basis of
distance from sanitation facilities. Most of the studies
employed interventions involving toilet promotion or
construction, with or without other measures such as
marketing and subsidies. Study outcomes consisted of
endpoints used to assess the impact of sanitation on
transmission pathways and included microbiological
assessments of drinking-water (sources and stored
household water), hand contamination, soil from
the toilet oor or household compound, and toilet
surfaces. Other measures included observations of
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Chapter 8
ies (around the toilets, in food preparation areas or
caught on/around eyes) or the presence of faeces in
or around the compound.
The studies showed mixed eects of the sanitation
intervention evaluated on most of the transmission
pathways, with most studies showing no effect.
There was no evidence of effects on drinking-
water quality, hand or sentinel toy contamination,
food contamination or contamination of soil or
surfaces. There was some evidence that sanitation
was associated with y reduction and a decrease in
observed faeces (although the overall assessment
was not statistically significant). Subgrouping of
studies on the basis of the level of sanitation coverage
suggested that sanitation interventions are more
eective at reducing observed levels of faeces when
the coverage starts at a low level and when there is a
large dierence between the coverage experienced
by the intervention and control groups. Studies
showed an inverse relationship between the distance
of a water source from a toilet and the level of faecal
contamination of the water source.
8.3.4 Improving health outcomes
How effective are different sanitation interventions
in improving health outcomes (including infectious
diseases, nutritional status, well-being and educational
outcomes)?
Infectious disease and nutrition
This section includes ve reviews:
• Freeman et al. (2017) updated a number of previous
systematic reviews on a range of health outcomes;
• Speich et al. (2016) examined the relationship
between access to, and use of, sanitation facilities
and incidence of intestinal protozoa infections;
• Majorin et al. (2018) considered interventions
improving the disposal of child faeces and their
impact on diarrhoea and STH infections;
• Ejemot-Nwadiaro et al. (2015) assessed the
eects of handwashing promotion on diarrhoeal
infections; and
• Yates et al. (2015) looked at the impact of water,
sanitation and hygiene interventions on people
living with HIV.
Freeman et al. (2017) updated reviews on the impact
of sanitation interventions on infectious disease
(diarrhoea, four soil-transmitted helminth (STH)
infections, schistosomiasis, trachoma) and nutritional
status outcomes (weight-for-age, weight-for-height
and height-for-age.
The eligibility criteria used by Freeman et al. (2017)
were based on the original systematic reviews and
varied slightly by review; however, eligible study
designs included RCTs, quasi-RCTs, non-randomized
controlled trials, controlled before-and-after (CBA)
studies, interrupted-time-series studies, cohort
studies and cross-sectional studies. A total of 171
eligible studies were identied, 84 of which were
included in the meta-analyses. For each disease
outcome, four types of meta-analysis were conducted:
• all studies – a pooling of the primary effect
estimates from the studies to estimate the overall
impact of sanitation;
• intervention studies – an analysis of the
experimental studies that specically assessed a
sanitation intervention to provide a more rigorous
pooled estimate;
• sanitation ladder – an assessment of different
types of sanitation on health impacts by pooling
estimates for dierent levels of sanitation service
(any sanitation versus none/non-use; improved
versus unimproved; improved versus shared); and
• stratified analysis – an exploration of study
population characteristics (such as study setting,
age group, water and soap availability).
Overall, greater access to sanitation was associated with
signicantly lower odds of diarrhoea (12% lower odds
for all studies combined; 23% lower odds in intervention
studies). Significantly lower odds of infection were
seen for the four major STH (A. lumbricoides, T. trichiura,
139
CHAPTER 8. EVIDENCE ON THE EFFECTIVENESS AND IMPLEMENTATION OF SANITATION INTERVENTIONS
Chapter 8
hookworm, S. stercoralis), with the odds associated with
sanitation ranging between 20% and 52% lower than
with no sanitation. When considering only intervention
studies, no reduction with improvements in access
to sanitation was seen in T. trichiura infection. Better
sanitation access was also found to have a protective
association against schistosomiasis and active trachoma
and to have a positive association with height-for-age.
However, most studies used observational designs,
pooled estimates showed substantial heterogeneity and
the quality of evidence was rated as low or very low. The
review by Freeman et al. (2017) found some evidence
of a borderline eect of sanitation interventions on
height-for-age z-score (MD 0.08; 95% CI0.00–0.16) but
no eect of sanitation on weight-for-age z-score nor on
weight-for-height z-score.
Speich et al. (2016) identied 54 eligible studies in
their systematic review on the eects of sanitation
and water treatment on intestinal protozoa infection
(Giardia intestinalis, Entamoeba histolytica, E. dispar,
Blastocystis hominis and Cryptosporidium spp.), of
which 36 were related to sanitation; 23 described
associations of sanitation availability, 11 examined
associations of the use of sanitation and two did not
clearly dierentiate between use and availability. The
majority of the sanitation studies were cross sectional
(n=29), with the remainder being case-control
(n=3), intervention (n=1), cohort (n=1) or joint cross-
sectional/case control (n=1) studies. The availability
or use of toilets was associated with signicantly
lower odds of infection with Entamoeba (44%
reduction, 95% CI: 26-58%) and Giardia intestinalis
(36% reduction, 95% CI: 19-49%), but not Blastocystis
or Cryptosporidium.
The impact of interventions to improve the disposal
of child faeces on diarrhoea and STH infection (A.
lumbricoides, T. trichiura, Ancylostoma duodenale and
Necator americanus) was reviewed by Majorin et al.
(2018). A total of 45 studies met the inclusion criteria
(11 RCTs, three CBA, 24 case-control, two controlled
cohort and ve cross-sectional studies). Interventions
included multi-component and education-only
interventions. The combined evidence suggested that
safe disposal of child faeces was associated with lower
odds of diarrhoea. The main evidence for this nding
came from case-control studies, which suggested that
disposal of child faeces in a toilet was associated with
24% lower odds of diarrhoea (95% CI: 12-34%), while
a child defecating in a toilet (rather than elsewhere)
was associated with 46% lower odds of diarrhoea
(95% CI: 10-67%). In the randomized controlled
trials, the sanitation interventions suggested a 7%
reduction in diarrhoea (although this result was not
statistically signicant), while the hygiene education
interventions were associated with a 17% reduction
(95% CI: 6-27%). Only two RCTs relating to STH and
child faeces disposal were identied and neither of
the interventions evaluated showed an impact on
helminth infection.
In their intervention review of hand washing promotion
for preventing diarrhoea, Ejemot-Nwadiaro et al. (2015)
identied 22 eligible individual RCTs and cluster-RCTs
that compared the eects of hand washing interventions
on diarrhoea episodes in children and adults with no
intervention. These included trials from child day-care
centres or schools in mainly high-income countries
(n=12), community-based trials in LMICs (n=9), and
one hospital-based trial among people with acquired
immune deciency syndrome (AIDS). The intervention
was dened as “activities that promoted hand washing
after defecation or after disposal of children’s faeces
and before eating, preparing or handling foods”.
Trials focused exclusively on hand washing and
those including hand washing as part of a broader
package of hygiene interventions were included if
they undertook analyses of eects of hand washing
on diarrhoea. Intervention outcomes were defined
as primary (episodes of diarrhoea dened as: acute/
primary diarrhoea, persistent diarrhoea or dysentery)
or secondary (diarrhoea-related death among children
or adults; behavioural changes, such as changes in the
140
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 8
proportion of people who reported or are observed
washing their hands after defecation, disposal of
children’s faeces, or before preparing or handling
foods; changes in knowledge, attitudes, and beliefs
about handwashing; all-cause-under five mortality;
and cost-eectiveness). The authors concluded that
hand washing promotion probably reduces diarrhoea
episodes in both child day-care centres in high-income
countries (30% reduction 95%CI: 15-42% n=9) and
among communities living in LMICs by about 30%
(LMIC - 28% reduction 95% CI: 17-38% n=8). However,
less is known about how to help people maintain hand
washing habits in the longer term. The hospital trial
with high-risk population showed signicant reduction
in mean episodes of diarrhoea (1.68 fewer) in the
intervention group, as well as increase in hand washing
frequency in the intervention group. No trials evaluating
or reporting the eects of hand washing promotion on
diarrhoea-related deaths, all-cause-under ve mortality
or costs were found.
Few studies examined the impact of sanitation on
specic population subgroups; however, some have
assessed the impact on people living with HIV as a
specic at-risk group due to biological and social
factors. Yates et al. (2015) conducted a systematic
review of the impact of water, sanitation and hygiene
interventions on the health and well-being of
people living with HIV, who are at a greater risk of
enteric infections from faecal-oral pathogens and
experience more severe symptoms compared to the
immunocompetent population. Sixteen studies were
included, of which four (one RCT, two cross-sectional
studies and one case-control study) considered the
impact of sanitation measures. Results were reported
in a variety of ways, but lack of access to household
sanitation was generally a signicant risk factor, in
that toilet access was found to be protective for
intestinal parasites and diarrhoea morbidity.
Cognition and school absence
In a review of the eects of sanitation on cognitive
development and school absence, Sclar et al. (2017)
identied 17 eligible studies (three RCTs, one non-
RCT, one CBA, nine cross-sectional and three cohort
studies). Twelve of the studies reported on school
absence, four reported on outcomes of cognitive
development and one reported on both outcomes.
The studies of access to household sanitation generally
found measures of improved cognitive ability. The
studies examining sanitation provision (household,
community or school sanitation) and school absence,
however, were more uncertain and, overall, lacked a
clear pattern. The GRADE score was very low for both
cognitive development and school absence.
Personal well-being
The relationship of sanitation with eight aspects of
well-being (privacy, shame, anxiety, fear, assault,
safety, dignity and embarrassment) was examined
by Sclar et al. (2018).
They identied 50 eligible studies (35 qualitative,
eight mixed methods and seven cross-sectional
studies), which considered aspects of relational
and subjective well-being for people using private
sanitation (n=11), shared sanitation (n=13), school
sanitation (n=22) and/or practicing open defecation
(n=18).
The study results were analysed using a set of well-
being codes and sanitation setting codes. The results
suggested that privacy and safety were the core
themes that inuenced the other aspects of well-being
(as indicated in the conceptual framework illustrated in
Figure 8.1). The authors noted that due to the skewed
geographical distribution of studies (e.g. 14 studies
were conducted in India) and a predominant focus on
141
CHAPTER 8. EVIDENCE ON THE EFFECTIVENESS AND IMPLEMENTATION OF SANITATION INTERVENTIONS
Chapter 8
the experiences of women and girls (19 studies), the
results may have limited generalizability.
8.4 Reviews of implementation
8.4.1 Impact of contextual factors
How do contextual factors (e.g. population, setting,
climate) and programmatic factors (e.g. policies,
regulation, roles of health and other sectors,
management at different levels of government)
inuence coverage and use of sanitation?
The systematic review conducted by Overbo et
al. (2016) drew from both peer-reviewed and grey
literature to examine the impacts of various policy and
programming strategies and enabling environment
factors (such as legislation, finance and politics)
on sanitation adoption and sustained use. A total of
68 eligible studies (31 peer-reviewed literature, 37
grey literature) from 27 countries were included in
the review (six qualitative, 25 quantitative, nine mixed
methods and 28 cases studies). The studies covered
improved household sanitation (n=59), household
sewer connections (n=8), faecal sludge management
(n=1), sewer/wastewater treatment (n=2), public
sanitation (n=2) and school sanitation (n=8). Ten of
the studies reported multiple sanitation technology
types. Fewer than half (28) of the studies reported on
the sustained use of sanitation facilities (described,
variously, as sanitation use, ending open defecation,
or safe disposal of excreta), with studies typically using
sustainability data collected through participant self-
Figure 8.1 Preliminary conceptual framework of the inuence of inadequate sanitation on well-being
Poor
well-being
Structural
Perceptions
Experiences
Contextual Factors
(contributing to privacy and safety issues
Inuence of inadequate sanitation on well-being
Individual Factors
(contributing to privacy and safety issues)
Environment
Social
Perceived lack of privacy
Dignity
Shame
Embarrasment
Anxiety
Lack of privacy/
Violation of privacy
Perceived lack of safety
Assault
(verbal, physical, and sexual)
e.g. broken doors, no locks,
low walls, poor lighting, slippery
oors, dirty
e.g. dangerous location,
high population density,
dry season, snakes, thorns
e.g. social norms, gender inequality,
gender-based violence
Gender
identity
Physical
ability
Life stage
(child, adolescent,
pregnant, elderly)
Residency status
(permanent,
itinerant, homeless)
Socioeconomic
status
Fear
142
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 8
reporting. All of the studies except one were set in
LMICs. The majority of programmes were based in rural
settings (62%) or the location was not reported (19%).
Data on factors serving as either enablers or barriers to
sanitation adoption and/or sustained use were collated
according to the framework shown in Figure 8.2.
Figure 8.2 Sanitation adoption and sustained use
review framework
Implementation
• Activities
• Actors
Outcomes
• Adoption
• Sustained use
• Equity
Community attributes
Physical environment
Enabling environment:
• Legislation & regulation
• Finance
• Government oversight
Most of the key ndings relate to household sanitation,
reecting the greater number of studies (59 out of 68).
The review reported that:
• Political will and leadership were essential to
programme success.
• More successful programming outcomes occurred
where there was coordination and collaboration
between dierent sectors and stakeholders.
• Harmonized policies between sectors were found
to mobilize political will and support for sanitation
programming.
• Access to credit aided success when it was well-
managed and there was community demand. The
study setting inuenced the need for (and eect
of) subsidies, but credit access was found to be
more effective when coupled with community
mobilization and a sense of ownership of the facility.
• Cultural norms and beliefs were found to vary
greatly between countries and settings, but
widespread acceptance of open defaecation
was a barrier to sanitation adoption. Sanitation
motivations for adoption and sustained use also
varied by setting but privacy, shame and social
pressure were frequently and widely reported.
• The physical environment (such as a high water
table, seasonal ooding and lack of space) was
cited as a barrier to adoption.
• Implementation activities (including house visits,
use of mass media and conventional information,
education and communication – IEC) were found
to be effective for raising awareness of, and
demand for, sanitation and they also played a role
in community mobilization.
• Monitoring and evaluation was cited as being
essential to facilitate strategic planning and create
political accountability.
The review identied numerous contextual factors
contributing to sanitation adoption and sustained
use. Many of these factors are interdependent, and
eective planning, monitoring and lesson-learning
in programme and policy implementation can help
address certain barriers.
8.5 Summary of evidence reviews
Table 8.1 provides an overall summary of the reviews.
143
CHAPTER 8. EVIDENCE ON THE EFFECTIVENESS AND IMPLEMENTATION OF SANITATION INTERVENTIONS
Chapter 8
Table 8.1 Summary of evidence reviews
Ref.
Chapter section
Type of review Aim(s)/
Objectives
Literature dates Languages Geographic/
economic
restrictions
Study designs Urban (U)/
Rural (R)
Assessment of
bias/score
Quality of
evidence/
score
How eective are dierent sanitation interventions in achieving and sustaining access to, uptake and use of sanitation?
Garn et al., 2017
8.3.1
Systematic review How dierent
sanitation
intervention types
impact toilet
coverage and use.
1950 - 31/12/15.
Published,
unpublished, in
press and grey
literature.
English, Spanish,
Portuguese,
French, German,
Italian.
None Household n=37
Randomized
controlled trials
(RCT) 10
Non RCT 1
Controlled before-
and-after (CBA) 6
Uncontrolled
before-and-after
11
Non-randomized
control trials 9
School n=4
RCT 1
Non RCT 3
Not stated Adapted Liverpool
Quality Appraisal
tool (LQAT) for
quantitative
intervention
studies. Most
studies indicated
some risk of bias"
GRADE.
Low to Very Low.
How dierent
structural &
design sanitation
characteristics are
associated with
toilet use.
N= 24
Experimental
and observation
designs,
quantitative
and qualitative.
Majority were
observational/
qualitative.
N/A N/A
Hulland et al.,
2015
8.3.1
Mixed methods
systematic review
Determination
of the factors
inuencing
sustained
adoption.
End date
01/10/13. Peer-
reviewed and grey
literature.
English, French,
German, Spanish.
LMIC No restriction on
study type
N=59
Not stated Quality assessed
using an adapted
7-point scale
developed by
Harden & Thomas
(2005), maximum
score 21. Overall
rigour scores
ranged from 8
to 21.
144
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 8
Ref.
Chapter section
Type of review Aim(s)/
Objectives
Literature dates Languages Geographic/
economic
restrictions
Study designs Urban (U)/
Rural (R)
Assessment of
bias/score
Quality of
evidence/
score
De Buck et al.,
2017
8.3.1
Mixed methods
systematic review
Quantitative
Eectiveness
of dierent
approaches
for promoting
handwashing
and sanitation
behaviour change.
1980 - March
2016; published,
unpublished, grey
literature
No language
restrictions
LMIC. Studies set
in institutions
(e.g. hospitals)
were excluded.
N=42
RCT 26
Quasi RCT 6
Non-randomized
control trials 8
Cohort 2
U 6
R 29
Cochrane risk
of bias tool.
All the studies
had evidence of
bias especially
in detection,
reporting and
attribution bias
GRADE. For most
assessments Low.
Evidence for
the sanitation
outcomes was
Low to Very Low
Qualitative Factors
inuencing the
implementation
of approaches
to promote
handwashing
and sanitation
behaviour change.
N=28
Qualitative studies
addressing factors
inuencing
implementation
of promotional
approaches (e.g.
grounded theory,
case studies,
phenomenological
studies,
ethnographic
research,
action research
& thematic
approaches to
qualitative data
analysis.
U 3
R 19
U & R 3
CASP (Critical
Appraisal Skills
Program)
checklist. Scores
ranged between
10 (maximum)
and 4.
Venkataramanan
et al., 2018
8.3.1
Mixed methods
systematic review
Assess evidence
quality,
summarize
impacts and
identify factors
aecting
implementation
and eectiveness
of CLTS.
Search conducted
in Dec 2015 and
updated March
2017
Not stated None stated No restriction
on study type.
N=200.
Quantitative 14
Qualitative 29
Case studies &
project reports
157
Not stated A quality appraisal
framework
for each study
type, based on 3
categories: quality
of reporting,
minimizing risk
of bias, and
appropriateness of
conclusions.
Table 8.1 Summary of evidence reviews (continued)
145
CHAPTER 8. EVIDENCE ON THE EFFECTIVENESS AND IMPLEMENTATION OF SANITATION INTERVENTIONS
Chapter 8
Ref.
Chapter section
Type of review Aim(s)/
Objectives
Literature dates Languages Geographic/
economic
restrictions
Study designs Urban (U)/
Rural (R)
Assessment of
bias/score
Quality of
evidence/
score
How eective are dierent sanitation interventions in reducing environmental faecal load?
Williams &
Overbo, 2015
8.3.2
Literature review Leakage along
the sanitation
service chain
for pit latrines,
septic systems &
sewerage
Web of Science
& Google Scholar
searched between
15/3/15 and
24/4/15. Peer-
reviewed journals
& grey literature
Not stated None stated Qualitative or
quantitative
ndings on
sanitation
technology
functionality,
microbial
contamination,
emptying,
transport,
treatment or
groundwater
contamination.
N/A N/A N/A
How eective are dierent sanitation interventions in reducing exposure to faecal pathogens?
Sclar et al., 2016
8.3.3
Systematic review Eectiveness
of sanitation
& sanitation
interventions
on faecal-oral
transmission
pathways.
1950 to Dec 2015.
Any publication
status.
English, Spanish,
Portuguese,
French, German,
Italian.
None Any. Study design
Faecal-oral
transmission
(n=23)
RCT 8
Non RCT 1
Quasi RCT 1
Cross sectional 11
Case control 1,
Cohort 1
Water supply
distance (n=6)
Cross sectional 6
U 10
R 15
U & R 3
Schools 1
Assessed in
experimental
studies using
adapted LQAT.
Average risk
of bias score
8/12 (with 12
indicating no
detection of bias)
- so relatively high
(range 5-11)
GRADE.
Low or Very Low.
Table 8.1 Summary of evidence reviews (continued)
146
WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 8
Ref.
Chapter section
Type of review Aim(s)/
Objectives
Literature dates Languages Geographic/
economic
restrictions
Study designs Urban (U)/
Rural (R)
Assessment of
bias/score
Quality of
evidence/
score
How eective are dierent sanitation interventions in improving health outcomes (including infectious diseases, nutritional status, well-being and educational outcomes)?
Freeman et al.,
2017
8.3.4
Systematic
review - updating
existing
systematic
reviews
Updating previous
reviews- general
points
From previous
review's endpoint
to Dec 31, 2015.
English, Spanish,
Portuguese,
French, German,
Italian.
Based on original
reviews
RCTs, quasi-
RCTs, non-RCT,
CBA studies,
interrupted-time-
series studies,
cohort studies and
cross-sectional
studies. Any
restrictions
followed the
design of
the original
systematic review.
See individual
reviews
Abridged LQAT
for experimental
studies
GRADE.
Updating
diarrhoea review
by Pruss-Ustun et
al. (2014)
N=33, 27 used in
meta-analysis
RCT 9
non RCT 7
Cross sectional 5
Case control 7
CBA 4
Case series 1
U 5
R 14
U & R 2
Schools 3
Serious risk (ave
5.3)
Low
Updating STH
review by Strunz
et al., 2014
N=65, 40 used
in meta-analysis
– varied by
helminth
A. lumbricoides
(n=39)
RCT 5
Non RCT 4
Cross sectional 27
CBA 1
Case series 1
Mixed methods 1
T. trichura (n=34)
RCT 4
Non RCT 3
Cross sectional 24
CBA 1
Mixed methods 1
Hookworm
(n=42)
RCT 4
Non RCT 2
Cross sectional 30
CBA 2
Case series 1
Mixed methods 1
Cohort 2
S stercoralis (n=9)
Non RCT 1
Cross sectional 7
Cohort 1
A lumbricoides
U 2
R 22
U&R 3
Schools 8
T. trichura
U 1
R 20
U&R 2
Schools 7.
Hookworm
R 26
U&R 5
Schools 6
S. stercoralis
R 6
U&R 1
Serious risk of bias
(depending on
STH 5 - 7.9)
A. lumbricoides
Very Low
T. trichura Very
Low
Hookworm Low
S. stercoralis – not
assessed.
Updating
trachoma review
by Stocks et al.
(2014)
N=46, 46 used in
meta-analysis
Active trachoma
(n=41)
RCT 3
Cross sectional 34
Case control 3
Case series 1
C. trachomatis
(n=10)
RCT 2
Cross sectional 8
Active
U 2
R 27
U&R 4 Schools 1.
C. trachomatis
R 7
Schools 1
Active trachoma
average 8.5
(serious risk)
C. trachomatis
10.5 (low risk)
Active trachoma
High
C. trachomatis
Moderate
Updating
schistosomiasis
review by Grimes
et al. (2014)
N=30, 23 used
in meta-analysis
depending upon
schistosome
Mansoni (n=23)
Cross sectional 22
Case control 1
Haematobium
(n=10)
Cross sectional 9
Case control 1
Mansoni
U 6
R 10
U&R 2
Schools 1.
Haemotobium
R 8
Schools 1
No intervention
studies - so no
score
No intervention
studies - so no
score
Updating nutrition
review by Dangour
et al. (2013)
N=17, 9 used in
meta-analysis
depending upon
measure
Wt for age and
underweight
(n=14)
RCT 7
Non RCT 6
Quasi RCT 1
Wt for height &
wasting (n=7)
RCT 4
Non RCT 3
Ht for age &
stunting (n=14)
RCT 8
Non RCT 6
Wt for age
R 11.
Wt for ht
R 5
Ht for age
R 12.
Stunting &
underweight 6 &
5.2. Wasting 3.5
Wt for age Low
Wt for ht Low
Wt for age Very
Low
Table 8.1 Summary of evidence reviews (continued)
147
CHAPTER 8. EVIDENCE ON THE EFFECTIVENESS AND IMPLEMENTATION OF SANITATION INTERVENTIONS
Chapter 8
Ref.
Chapter section
Type of review Aim(s)/
Objectives
Literature dates Languages Geographic/
economic
restrictions
Study designs Urban (U)/
Rural (R)
Assessment of
bias/score
Quality of
evidence/
score
How eective are dierent sanitation interventions in improving health outcomes (including infectious diseases, nutritional status, well-being and educational outcomes)?
Freeman et al.,
2017
8.3.4
Systematic
review - updating
existing
systematic
reviews
Updating previous
reviews- general
points
From previous
review's endpoint
to Dec 31, 2015.
English, Spanish,
Portuguese,
French, German,
Italian.
Based on original
reviews
RCTs, quasi-
RCTs, non-RCT,
CBA studies,
interrupted-time-
series studies,
cohort studies and
cross-sectional
studies. Any
restrictions
followed the
design of
the original
systematic review.
See individual
reviews
Abridged LQAT
for experimental
studies
GRADE.
Updating
diarrhoea review
by Pruss-Ustun et
al. (2014)
N=33, 27 used in
meta-analysis
RCT 9
non RCT 7
Cross sectional 5
Case control 7
CBA 4
Case series 1
U 5
R 14
U & R 2
Schools 3
Serious risk (ave
5.3)
Low
Updating STH
review by Strunz
et al., 2014
N=65, 40 used
in meta-analysis
– varied by
helminth
A. lumbricoides
(n=39)
RCT 5
Non RCT 4
Cross sectional 27
CBA 1
Case series 1
Mixed methods 1
T. trichura (n=34)
RCT 4
Non RCT 3
Cross sectional 24
CBA 1
Mixed methods 1
Hookworm
(n=42)
RCT 4
Non RCT 2
Cross sectional 30
CBA 2
Case series 1
Mixed methods 1
Cohort 2
S stercoralis (n=9)
Non RCT 1
Cross sectional 7
Cohort 1
A lumbricoides
U 2
R 22
U&R 3
Schools 8
T. trichura
U 1
R 20
U&R 2
Schools 7.
Hookworm
R 26
U&R 5
Schools 6
S. stercoralis
R 6
U&R 1
Serious risk of bias
(depending on
STH 5 - 7.9)
A. lumbricoides
Very Low
T. trichura Very
Low
Hookworm Low
S. stercoralis – not
assessed.
Updating
trachoma review
by Stocks et al.
(2014)
N=46, 46 used in
meta-analysis
Active trachoma
(n=41)
RCT 3
Cross sectional 34
Case control 3
Case series 1
C. trachomatis
(n=10)
RCT 2
Cross sectional 8
Active
U 2
R 27
U&R 4 Schools 1.
C. trachomatis
R 7
Schools 1
Active trachoma
average 8.5
(serious risk)
C. trachomatis
10.5 (low risk)
Active trachoma
High
C. trachomatis
Moderate
Updating
schistosomiasis
review by Grimes
et al. (2014)
N=30, 23 used
in meta-analysis
depending upon
schistosome
Mansoni (n=23)
Cross sectional 22
Case control 1
Haematobium
(n=10)
Cross sectional 9
Case control 1
Mansoni
U 6
R 10
U&R 2
Schools 1.
Haemotobium
R 8
Schools 1
No intervention
studies - so no
score
No intervention
studies - so no
score
Updating nutrition
review by Dangour
et al. (2013)
N=17, 9 used in
meta-analysis
depending upon
measure
Wt for age and
underweight
(n=14)
RCT 7
Non RCT 6
Quasi RCT 1
Wt for height &
wasting (n=7)
RCT 4
Non RCT 3
Ht for age &
stunting (n=14)
RCT 8
Non RCT 6
Wt for age
R 11.
Wt for ht
R 5
Ht for age
R 12.
Stunting &
underweight 6 &
5.2. Wasting 3.5
Wt for age Low
Wt for ht Low
Wt for age Very
Low
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Chapter 8
Ref.
Chapter section
Type of review Aim(s)/
Objectives
Literature dates Languages Geographic/
economic
restrictions
Study designs Urban (U)/
Rural (R)
Assessment of
bias/score
Quality of
evidence/
score
Speich et al., 2016
8.3.4
Systematic review Assess the
relationship
between access
to, and use
of, sanitation
facilities (and
water treatment)
and infection
with intestinal
protozoa.
Database
inception to June
30, 2014
Published papers.
No restrictions None No restrictions on
study type.
N=36
Cross sectional 30
Case control 3
Intervention 1
Cohort 1
Combined cross-
sectional/cohort 1
Not stated No information Based on GRADE.
Most studies
classed as
Moderate or Low.
Majorin et al.,
2018
8.3.4
Systematic review Assess the
eectiveness of
interventions to
improve disposal
of child faeces on
the prevention of
diarrhoea and STH
infections.
Search dates
depend on the
database and
span between
November 2014
and June 2015.
Includes grey
literature.
Not stated None Any controlled
trial.
N=45
Cluster RCT 11
CBA 3
Case control 24
Controlled
cohort 2
Cross sectional 5
Case control
studies were
classed on
recruitment site
(e.g. health care
settings). For the
other study types
(n=21) R 16
Risk of bias
accounted for in
GRADE score. Risk
of confounding
and adjustment
for confounding
specied for each
study.
GRADE -
categorised by
outcome. Very
Low or Low.
Ejemot- Nwadiaro
et al., 2015
8.3.4
Intervention
review
Assess the eects
of handwashing
promotion
interventions
in diarrhoeal
episodes.
1966 to May 2015.
Peer-reviewed
and grey
literature.
English (not
specied)
None RCTs n=22 Both U & R
locations, but
not part of
the ndings
stratication.
Cochrane risk
of bias tool.
The risk of any
type of bias was
predominantly
low or unclear in
all studies.
GRADE
Ranged from High
to Low.
Yates et al., 2015
8.3.4
Systematic review Impact of WASH
interventions on
people living with
HIV.
5 outcomes
considered but
papers only found
for morbidity
(n=16) and
mortality (n=2).
Jan 1995 to June
2014.
Not stated Focus was on
'resource-limited
countries.'
Sanitation n=4
RCT 1
Cross sectional 2
Case control 1
Not stated Not stated Unclear how
scored but classed
as strong, medium
or weak based
on study design,
cohort population
and sample size.
RCT was classed
as strong, other
studies as weak.
Table 8.1 Summary of evidence reviews (continued)
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CHAPTER 8. EVIDENCE ON THE EFFECTIVENESS AND IMPLEMENTATION OF SANITATION INTERVENTIONS
Chapter 8
Ref.
Chapter section
Type of review Aim(s)/
Objectives
Literature dates Languages Geographic/
economic
restrictions
Study designs Urban (U)/
Rural (R)
Assessment of
bias/score
Quality of
evidence/
score
Sclar et al., 2017
8.3.4
Systematic review Assess the impact
of sanitation
(access, quality or
specic sanitation
intervention) at
household, school
or community
level on cognitive
development and
absence from
school or work.
1950 and Dec
2015. Any
publication status.
English, Spanish,
Portuguese,
French, German,
Italian.
None No restrictions on
study type.
N=17
RCT 3
Non-RCT 1
Cross sectional 9
CBA 1
Cohort 3
Not stated Modied LQAT.
Both cognitive
development and
school absence
papers were
assessed as have
a very serious risk
of bias.
GRADE. Both
aspects were
scored Very Low.
Sclar et al., 2018
8.3.4
Systematic review Assess the impact
of sanitation on
well-being.
1950 to November
2016. Any
publication status
English, Spanish,
Portuguese,
French, German,
Italian.
None No restrictions on
study type.
N=50
Qualitative 35
Mixed methods 8
Cross sectional 7
Quantitative
studies LQAT
Qualitative studies
assessed using a
17-point checklist
developed by
authors (based on
Walsh & Downe,
2006; Harden et
al., 2009).
GRADE-CERQual.
The assessment
was done on a
theme basis and
results varied from
Very Low to High
condence.
How do contextual factors (e.g. population, setting, climate) and implementation aspects (e.g. policies, regulations, roles of the health and other sectors, management at dierent levels of government) inuence
access to as well as uptake and use of dierent interventions?
Overbo et al., 2016
8.4
Systematic review Evaluate how
sanitation
adoption and
sustained use
have been
aected by
sanitation
programmes, their
implementation
and the enabling
environment in
which they are
carried out.
Publications
after 1990. Peer-
reviewed and grey
literature.
English None No restrictions on
study type.
N=68
Qualitative 6
Quantitative 25
Mixed methods 9
Case studies 28
Split is reported
on a programme
(rather than
study) basis
U 6
R 48
U & R 7
Assessed as
strong, moderate
or weak using
LQAT, quality
criteria adapted
from Harden et al.
(2009) or methods
adapted from
Atkins & Sampson
(2002).
Table 8.1 Summary of evidence reviews (continued)
CASP – critical appraisal skills program; CBA – controlled before-and-after; CERQual – condence in evidence from review of qualitative research; CLTS – community-led total sanitation; LMIC – low- and middle-income countries; LQAT – Liverpool
quality appraisal tool; NA – not applicable; RCT – randomized control trial.
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Atkins C, Sampson J (2002). Critical appraisal guidelines for single
case study research. ECIS 2002 Proceedings.
Dangour AD, Watson L, Cumming O, Boisson S, Che Y, Velleman
Y et al. (2013). Interventions to improve water quality and
supply, sanitation and hygiene practices, and their eects on the
nutritional status of children. Cochrane Database Sys Rev 8.
De Buck E, Van Remoortel H, Hannes K, Govender T, Naidoo S,
Avau B et al. (2017). Promoting handwashing and sanitation
behaviour change in low- and middle-income countries: a mixed-
method systematic review. 3ie Systematic Review 36. London:
International Initiative for Impact Evaluation (3ie).
Ejemot-Nwadiaro RI, Ehiri JE, Arikpo D, Meremikwu MM, Critchley
JA (2015). Hand washing promotion for preventing diarrhoea.
Cochrane Database Syst Rev. 9:CD004265.
Freeman MC, Garn JV, Sclar GD, Boisson S, Medlicott K, Alexander
KT et al. (2017). The impact of sanitation on infectious disease and
nutritional status: A systematic review and meta-analysis. Int J Hyg
Environ Health. 220:928-949.
Garn JV, Sclar GD, Freeman MC, Penakalapati G, Alexander KT,
Brooks P et al. (2017). The impact of sanitation interventions on
latrine coverage and latrine use: A systematic review and meta-
analysis. Int J Hyg Environ Health. 220:329-340.
Grimes JE, Croll D, Harrison WE, Utzinger J, Freeman MC,
Templeton MR (2014). The relationship between water, sanitation
and schistosomiasis: a systematic review and meta-analysis. PLoS
Negl Trop Dis. 8: e3296.
Harden A, Brunton G, Fletcher A, Oakley A (2009). Teenage
pregnancy and social disadvantage: systematic review integrating
controlled trials and qualitative trials. BMJ 339: b4254.
Harden A, Thomas J (2005). Methodological issues in combining
diverse study types in systematic reviews. Int J Soc Res Methodol.
8: 257-271.
Hulland K, Martin N, Dreibelbis R, DeBruicker Valliant J, Winch
P (2015). What factors aect sustained adoption of safe water,
hygiene and sanitation technologies? A systematic review of
literature. London: EPPI-Centre, Social Science Research Unit, UCL
Institute of Education, University College London (http://eppi.ioe.
ac.uk/cms/Default.aspx?tabid=3475, accessed 21 March 2018).
Majorin F, Torondel B, Chan G, Clasen TF (2018). Interventions to
improve disposal of child faeces for preventing diarrhoea and soil-
transmitted helminth infection. Cochrane Review (in press)
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identied challenges in applying GRADE to complex interventions
and suggested an extension to GRADE. J Clin Epidemiol. 70: 191-
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Movsisyan A, Melendez-Torres GJ, Montgomery P (2016b)
Outcomes in systematic reviews of complex interventions never
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simple interventions. J Clin Epidemiol. 78: 22-33.
Overbo A, Williams A, Ojomo E, Joca L, Cardenas H, Kolsky P
et al. (2016). The inuence of programming and the enabling
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systematic review. The Water Institute at UNC, Chapel Hill, NC,
USA.
Pruss-Ustun A, Bartram J, Clasen T, Colford Jr. JM, Cummings O,
Curtis V et al. (2014). Burden of disease from inadequate water,
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Sclar GD, Garn JV, Penakalapati G, Alexander KT, Krauss J, Freeman
MC et al. (2017). Eects of sanitation on cognitive development
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220:917-927.
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Freeman MC et al. (2016). Assessing the impact of sanitation
on indicators of faecal exposure along principal transmission
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Alexander K et al. (2018). Exploring the Relationship Between
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sanitation and water treatment on intestinal protozoa infection: a
systematic review and meta-analysis. Lancet Infect Dis. 16:87-99.
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MC (2014). Eect of water, sanitation and hygiene on the
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(2014). Water, sanitation, hygiene, and soil-transmitted helminth
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151
CHAPTER 9. RESEARCH NEEDS
Chapter 9
9.1 Pursuing a sanitation research
agenda
Although the recommendations included in these
guidelines are supported by evidence, there is need
for further research, particularly to provide more
information on eective policies and implementation
practices. Research needs emerging from the
evidence review (Chapter 8) are detailed below.
Execution of the research agenda should include
participation by all stakeholders. Research should
involve various disciplines (behavioural science,
economics, engineering, environmental science,
epidemiology, management, medicine, microbiology
and public policy, among others) and should be
conducted in a cross-disciplinary manner.
It is important that the research actively involves local
individuals and institutions to strengthen local insight
into study design, to build capacity, and to improve
local engagement and uptake of findings within
policies at the local and national level.
Much of the required research needs to be done with
the cooperation of sanitation intervention teams in the
context of programmatically-delivered interventions.
While carefully controlled efficacy studies provide
valuable information and are useful for proof of
concept, there is a greater need for rigorous and long-
term evaluations of actual interventions as delivered
on the ground and at scale. By combining such studies
with economic evaluations, data should be generated
which allow reporting on cost-eectiveness and cost
benets, allowing policymakers to compare returns on
investments in multiple sectors.
9.2 Research agenda
Areas that require further research emerging for the
evidence reviews (Chapter 8) are summarized below.
It is not intended to be static and research needs will
change as conditions alter and new ndings emerge.
9.2.1 Strategies for encouraging governments
to prioritize, encourage and monitor
sanitation
The recommendations included in these guidelines
focus on the role of governments in advancing
universal coverage and use of sanitation. There is
little research, however, on the policies and strategies
(including collaboration with partners from civil
society and the private sector) that governments
should adopt and implement in order to pursue these
recommendations eectively. There is role for policy
analysts, political scientists, economists, public sector
managers and others to identify strategies, to help
formulate policy and to evaluate approaches.
9.2.2 Creating an enabling environment
There is very little information on the effects of
enabling environment components (institutions,
policy, strategy, planning, regulation, enforcement
and capacity) on sanitation adoption and sustained
use in the peer-reviewed literature and a recent review
had to rely mainly on case study reports from the grey
literature (Overbo et al., 2016). Few studies (peer-
reviewed or otherwise) analysed the eects of the
enabling environment on adoption or use of sewer
connections, faecal sludge management services,
wastewater treatment, school sanitation or public
Chapter 9
RESEARCH NEEDS
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sanitation. Also, little evidence was found on the
impacts of legislation, regulations and programme
funding availability. There is a need to understand
how governments, NGOs, donors and the private
sector can support the large-scale implementation
of eective sanitation programmes and strategies,
as well as drivers and barriers.
9.2.3 Improving coverage and securing correct,
consistent, sustained use
There are currently only limited studies which assess
the eectiveness of programmes to achieve coverage
of sanitation in an entire community and to sustain
toilet use after the conclusion of the programme. This
research needs to include an examination of the extent
to which the promoted facilities meet the needs of
users, while ensuring a safe sanitation system.
Research has shown the challenges of achieving
optimal use of sanitation facilities (Garn et al., 2017).
To date, however, there have been few rigorous
studies demonstrating eective behaviour change
strategies and the economic incentives that can
be applied to encourage correct, consistent and
sustained use of sanitation facilities. It is especially
important to undertake formative research and
evaluate interventions over the medium and long-
term through operational research to address
questions on:
• the longevity and quality of facilities and factors
influencing them, including as these relate to
slippage to open defecation and other poor
practices;
• emptying and full pit replacement behaviours
(particularly in urban settings);
• treatment/disposal practices;
• dierences in need and use depending on factors
such gender, age, ethnicity, culture, disability,
income etc;
• sanitation technology preferences (and their
impact on the sanitation service chain);
• the impact of sanitation by-laws on household
investment and behaviours;
• products and materials that enable improved
behaviours and practices (human-centred design);
• changes in local norms; and
• factors that may lead populations to return to open
defecation.
9.2.4 Estimating health impacts from sanitation
interventions
While the evidence on health impacts is sucient
to support broad recommendations on improving
sanitation, it is still limited and of generally poor
quality. Most research conducted to date has utilized
observational (often cross-sectional) study designs.
To improve the strength of the evidence on health
impacts, there is a need for longer-term studies in
multiple settings following randomized or other
rigorous designs that evaluate all exposure pathways.
A growing body of evidence indicates that disease
reduction will not be detected unless the coverage
of sanitation use at community-level is high (>70%).
While adoption of sanitation by a community oers
the potential to benefit those members who are
reluctant to adopt, such “herd immunity” has only
recently been investigated (Fuller et al., 2016). Further
work in this area could help to establish the thresholds
necessary to achieve such externalities and help
establish sanitation as a service that benets the entire
community, and therefore warrants public investment.
Therefore, at lower levels of coverage, studies should
focus on well-being and equity outcomes as well as
changes in faecal load in the environment or exposure
as intermediate outcomes associated with the
intervention. Eectiveness studies and programme
evaluations can also help to assess the impact of
potentially scalable sanitation interventions (Section
9.2.3). Lessons should also be learned from trials
that failed to achieve their expected outcomes (e.g.
Boisson et al., 2014; Humphrey et al., 2015; Luby et
al., 2018; Null et al., 2018; Sinharoy et al., 2017; Patil
et al., 2014).
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CHAPTER 9. RESEARCH NEEDS
Chapter 9
There is need for more research:
• to explore the impact of sanitation on physical and
cognitive development and its longer-term eects
on productivity and economic development;
• to comprehensively characterize the sanitation
facility needs of the target population and desired
quality (including gender-related needs) through
operational research;
• to examine the potential impacts of sanitation on
priority pathogens (see Table 6.1);
• to examine the impact of sanitation on other
health outcomes and on the risk of co-morbidities
(such as gastrointestinal illness and respiratory
infection); including research to: develop cheap
and reliable methods for assessing environmental
enteric dysfunction (EED) prevalence; compare the
health and nutrition impacts of diarrhoeas and
EED and the extent to which diarrhoea statistics
can serve as a proxy indicators for EED prevalence
and severity; and assess the energy and protein
demands caused by EED); and
• to examine the impact of climate change on
sanitation-related health outcomes, in terms of
both the overall sustainability and performance
of sanitation systems, and on sanitation-related
pathogens and vectors.
9.2.5 Improving methods for assessing presence
of and exposure to sanitation-related
pathogens in the environment
While eld and laboratory methods used to assess
the presence of or exposure to environmental
contaminants are evolving, the eld methods utilized
still commonly rely on faecal indicator bacteria (such
as E. coli, S. faecalis and thermotolerant coliforms).
However, evidence indicates that such indicators
can have environmental origins and, thus, may not
provide accurate estimates of faecal exposure. There
is also a need for more widespread use of molecular
microbial analysis methods in research, which are
currently largely conned to specialized laboratories
with substantial requirements for equipment and
reagents, as they can be used to target pathogens
rather than faecal indicators.
The identification of locally-important key faecal
transmission pathways can provide valuable
information for the prioritization of interventions.
There is also a compelling need for approaches that
capture a person’s full personal exposure to faecal
pathogens, not just methods that assess the presence
and quantity of pathogens through the various
transmission pathways.
9.2.6 Preventing the discharge of faecal
pathogens into the environment
In order to understand and address the hazard to public
health resulting from the unsafe return of human
excreta to the environment, it is necessary to determine
where excreta “leaks” from the sanitation service chain.
There is currently limited information, for example,
on the proportion of untreated faecal sludge that is
being disposed of (via a range of practices) to surface
waters, agricultural land and within communities.
Future research on pit emptying and faecal sludge
management behaviour should report, specically, on
the location of disposal in order to better characterize
the associated public health risks. There is also a paucity
of literature on the fate of pathogens in euent from on-
site systems as it enters the environment (e.g. into soil,
groundwater, drains etc.) and the magnitude of related
public health risks. Initial eorts have been made to
analyse pathogen entry to the environment, exposure
and resultant health risks (Mills et al., 2018), however
signicant additional empirical evidence is required to
develop a robust approach.
Critical gaps identied include the characteristics and
fate of collected faecal sludge, and the performance
of treatment processes. While some studies reported
volumes of faecal sludge collected, treated, and
properly disposed in certain cities, there were no
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estimates or studies found for many regions. Having
more reliable estimates from collection through
disposal would better illustrate regional gaps and
opportunities within the sanitation service chain.
Similarly, there are global estimates for wastewater
that is treated but the treatment performance and
in some case level of treatment is unknown. The
results from the reviewed studies show, even with
advanced treatment processes, some wastewater
euent still contains high levels of pathogens. There
is inadequate evidence, on the fate of different
pathogens within treatment systems (e.g. helminths)
(Williams & Overbo, 2015). As the eects of climate
change continue to unfold, operational research is
needed to understand its impact on the eectiveness
of sanitation systems in consistently preventing
pathogen discharge into the environment.
9.2.7 Exploring alternative designs and services
Increasing population density and environmental
stress (including water scarcity) potentially require
alternatives to individual household toilets and water-
based sanitation systems. While studies have raised
concerns about adverse health outcomes associated
with shared sanitation (Heijnen et al., 2014; Baker et
al.,2016), this may be attributable to factors that can
be improved programmatically such as poor access,
maintenance and waste management (Heijnen et al.,
2014 and 2015). Small scale, innovative solutions at
the user interface and throughout the service chain
have reduced or eliminated the need for water for
ushing toilets and transporting waste.
There is a particular need for innovative solutions
driven by evidence from operational research for
emptying of on-site sanitation facilities in low-income
and high-density settings and for safe and sustainable
sludge transport and disposal services to ensure that
the waste is properly treated or contained. There is
also a lack of solutions for improving containment
and the exposure to euent from on-site systems
discharged to open drains. There is also a need for
improved decision-making frameworks to assist in
appropriate investments across on-site, decentralised
and centralised solutions, balancing economic, public
health and environmental objectives.
The potential of the private sector, separately or
in partnership with governments and civil society,
to contribute to the development and scaling up
of sanitation solutions especially in neglected or
underserved settings requires investigation. Further
research is required to create, assess and produce
acceptable, aordable and environmentally sustainable
sanitation facilities and waste management services
that address these and other challenges.
9.2.8 Ensuring that proposed sanitation
interventions are culturally-appropriate,
respect human rights and reflect human
dignity
Sanitation presents major cultural, religious, social
and political challenges. However, comparatively
little research has been undertaken on the extent to
which sanitation initiatives (in terms of both facilities
and promotional methods) are consistent with the
values, traditions and norms of target populations
in a way that both enables use of safe sanitation
systems and protects the health and well-being of
all individuals. While user preferences and practices
are sometime described in literature, operational
research is needed to develop and evaluate the
extent to which interventions respond to specic
cultural needs.
While sanitation has been acknowledged as a
human right and promoted as a means of advancing
personal dignity, there is little research to provide
guidance on the manner in which sanitation can
best meet all human rights criteria for sanitation
services for all users and communities in terms of
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CHAPTER 9. RESEARCH NEEDS
Chapter 9
availability, accessibility, quality, aordability and
acceptability. For instance, research gaps exist in
relation to acceptability (for example, sanitation
technology preferences of different groups, and
their impact on the sanitation service chain), as well
as aordability (for example, consumer nancing
options/alternatives and the best modalities and
targeting methods to enable poor households and
groups to gain access to improved services). As
these criteria aect the adoption, consistent use,
functionality and sustainability of sanitation systems,
they should be addressed as a fundamental part of
sanitation programme evaluations and studies.
9.2.9 Mitigating occupational exposures
Sanitation workers are at risk of certain occupational
health hazards since their work may require heavy
labour (Charles, Loomis & Demissie, 2009; Tiwari,
2008), exposure to toxic gases and cleaning agents
(Knight & Presnell, 2005; Lin et al., 2013; Tiwari, 2008),
and handling of solid waste co-disposed in toilets in
addition to the exposure to faecal sludge and sewage.
Lack of PPE, unsafe practices and frequent exposure
to faecal sludge and sewage can lead to a wide array
of adverse health eects (e.g. gastrointestinal and
other infections, respiratory problems, dermatological
issues musculoskeletal disorders and physical injuries)
Glas, Hotz & Steen, 2001; Jegglie et al., 2004; Thorn
& Kerekes, 2001; Tiwari, 2008). Research is needed on
eective methods for mitigating the identied risks,
particularly in low- and middle-income countries.
9.2.10 Reducing adverse ecological effects
While the focus of these guidelines is on human
health, indiscriminate sanitation practices that
adversely impact the environment can result in both
short- and long-term hazards to health. Water, for
example, can be polluted with compounds from
on-site sanitation through three main pathways,
namely: pit leaching, pit overow and indiscriminate
disposal of untreated or poorly treated wastes. While
much of the sanitation literature focuses on microbial
contaminants, such pollution is also associated with
chemical contaminants, such as nitrates, chloride,
phosphate and ammonia (Graham & Polizzotto, 2013).
The presence of these chemicals in surface waters
can lead to harmful algal blooms, which may result
in a build-up of toxins in the food chain (e.g. sh
and seafood), reduced oxygen levels and possible
sh death. There is a need for research to assess the
impacts of these practices on human health and to
develop cost-eective mitigation strategies in LMICs.
9.2.11 Elaborating the links between sanitation
and animals and their impact on human
health
The links between animals and sanitation-related
health impacts are inconsistently addressed in
sanitation research and programmes. Factors include
household animals acting as mechanical vectors
transporting human faecal pathogens (Mandell et al.,
2009), animal consumption of human faeces as part
of the pathogen (usually parasite) lifecycle (WHO,
UD; Webber 2005), animal faeces carrying pathogens
that infect humans (Penakalapati), and animal faeces
contributing to breeding of ies that act as mechanical
vectors for human pathogens (faecal and otherwise,
as in the case of trachoma) (Fotedar, 2001; Khin et
al., 1989; Stocks et al., 2014; Szostakowska et al.,
2004). These multiple interactions are complex and
dicult to evaluate and may be a signicant yet poorly
understood factor in sanitation trials that failed to
achieve their expected health outcomes.
While animal faeces have not been addressed
specifically in these Guidelines, they have a
potentially detrimental eect on human health. A
systematic review (Penakalapati et al., 2017), which
examined the human health impacts of exposure
to poorly managed animal faeces transmitted via
water, sanitation and hygiene-related pathways
found that few studies have evaluated control
measures such as reducing cohabitation with animals,
provision of animal faeces scoops, controlling animal
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WHO GUIDELINES ON SANITATION AND HEALTH
Chapter 9
movement, creating safe child spaces, improving
veterinary care and hygiene promotion. Possible
areas of further research include: behaviours related
to points of contact with animal faeces; animal
faecal contamination of food; cultural behaviours
of animal faecal management; the importance of
animal faeces management for controlling y and
other insect vector populations; acute and chronic
health risks associated with exposure to animal
faeces; and factors inuencing concentrations and
shedding rates of pathogens originating from animal
faeces. Additionally, the trade-os between economic
aspects of animal husbandry practices, nutrition,
food security and disease control objectives need
to be studied through formative and operational
research, as these and aect the likely eectiveness
of sanitation and disease control interventions.
9.2.12 Investigating the issues around sanitation
and gender
The special issues around gender and sanitation,
which are often location/context specic, and the
means of overcoming these challenges warrants
further research. Women and girls often face
particular challenges in having access to and
using adequate sanitation facilities. These include
anxiety over personal security, privacy issues and
reliance on sanitation facilities for menstrual hygiene
management. On the other hand, in some settings
(where open defecation is common), research has
shown that toilet use is lower among men and
children than among women and girls (Sinharoy et
al, 2017; Coey et al., 2014) due to aspects such as
work settings or cultural practices. The need to ensure
non-exclusion from toilet access and use on the basis
of gender, and to explicitly accommodate all binary
and non-binary gender identities, is increasingly
recognised in sanitation programmes and literature
(Benjamin & Hueso, 2017; Boyce et al., 2018); however,
social and operational participatory and inclusive
research is needed to guide laws and standards that
support universal access for all genders, particularly
with regards to toilets in institutions, work places and
public places and in LMICs.
157
CHAPTER 9. RESEARCH NEEDS
Chapter 9
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et al. (2016). Sanitation and Hygiene-Specic Risk Factors for
Moderate-to-Severe Diarrhea in Young Children in the Global
Enteric Multicenter Study, 2007-2011: Case-Control Study. PLoS
Med. 13(5): e1002010.
Benjamin C, Hueso A (2017). LGBTI and sanitation: what we know
and what the gaps are. 40th WEDC International Conference,
Loughborough, UK, 2017. Local action with international
cooperation to improve and sustain water, sanitation and
hygiene services. Paper ID 2649.
Boisson S, Sosai P, Ray S, Routray P, Torondel B, Schmidt W-P
(2014). Promoting latrine construction and use in rural villages
practicing open defecation: process evaluation in connection
with a randomised controlled trial in Orissa, India. BMC Res
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Boyce P, Brown S, Cavill S, Chaukekar S, Chisenga B, Dash
M, Dasgupta RK, De La Brosse N, Dhall P, Fisher J, Gutierrez-
Patterson M, Hemabati O, Hueso A, Khan S, Khurai S, Patkar
A, Nath P, Snel M and Thapa K (2018). Transgender-inclusive
sanitation: insights from South Asia. Waterlines 37:2.
Charles LE, Loomis D, Demissie Z (2009). Occupational hazards
experienced by cleaning workers and janitors: A review of the
epidemiologic literature. Work. 34(1): 105-116.
Coey D, Gupta A, Hathi P, Khurana N, Spears D, Srivastav N et al.
(2014). Revealed preference for open defecation. Econ Polit Wkly.
49: 43-55.
Fotedar R (2001) Vector potential of houseies (Musca
domestica) in the transmission of Vibrio cholerae in India. Acta
Trop. 78(1): 31-34.
Fuller JA, Eisenberg JN. (2016). Herd protection from drinking
water, sanitation and hygiene interventions. Am J Trop Med Hyg.
95(5): 1201-1210.
Garn JV, Sclar GD, Freeman MC, Penakalapati G, Alexander KT,
Brooks P et al. (2017). The impact of sanitation interventions on
latrine coverage and latrine use: A systematic review and meta-
analysis. Int J Hyg Environ Health 220: 329-340.
Glas C, Hotz P, Steen R. (2001). Hepatitis A in workers exposed
to sewage: a systematic review. J Occup Environ Med. 58: 762-
768.
Graham JP, Polizzotto ML (2013). Pit latrines and their impacts
on groundwater quality: A systematic review. Environ Health
Perspect. 121(5): 521–530.
Heijnen M, Cumming O, Peletz R, Chan GK, Brown J, Baker K,
Clasen T (2014). Shared Sanitation versus Individual Household
Latrines: A Systematic Review of Health Outcomes. PLoS One.
17;9(4): e93300.
Heijnen M, Routray P, Torondel B, Clasen T. (2015). Neighbour-
shared versus communal latrines in urban slums: a cross-
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demographics, accessibility, privacy, use and cleanliness. Trans R
Soc Trop Med Hyg. 109(11): 690-699.
Humphrey JH, Jones AD, Manges A, Mangwada G, Maluccio JA,
Mbuya MN et al. (2015). The Sanitation Hygiene Infant Nutrition
Ecacy (SHINE) Trial: Rationale, Design and Methods. Clin Infect
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Jegglie S, Steiner D, Joller H, Tschopp A, Steen R, Hotz P (2004).
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Knight LD, Presnell SE (2005). Death by sewer gas: Case report of
a double fatality and review of the literature. Am J Forensic Med
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Lin J, Aoll J, Niclass Y, Velasco MI, Wünsche L, Pika J, Starkenmann
C (2013). Qualitative and quantitative analysis of volatile
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Luby SP, Rahman M, Arnold BF, Unicomb L, Ashraf S, Winch PJ et
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et al. (2016). The inuence of programming and the enabling
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Patil SR, Arnold BF, Salvatore AL, Briceno B, Ganguly S, Colford JM
Jr et al. (2014). The eect of India’s total sanitation campaign on
defecation behaviors and child health in rural Madhya Pradesh: a
cluster randomized controlled trial. PLoS Med. 11(8): e1001709.
Sinharoy SS, Schmidt WP, Wendt R, Mfura L, Crossett E, Grépin KA
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Szostakowska B, Kruminis-Lozowska W, Racewicz M, Knight R,
Tamang L, Myjak P et al. (2004). Cryptosporidium parvum and
Giardia lamblia recovered from ies on a cattle farm and in a
landll. Appl Environ Microbiol. 70(6): 3742-4.
Thorn J, Kerekes E (2001). Health eects among employees in
sewage treatment plants: A literature survey. Am J Ind Med.
40:170-179.
Tiwari R (2008). Occupational health hazards in sewage and
sanitary workers. Indian J Occup Environ Med. 12(3): 112-115.
Webber R (2005). Communicable Disease Epidemiology and
Control, Cambridge, MA, USA, CABI Publishing.
Williams AR, Overbo A (2015). Unsafe return of human excreta to
the environment: A literature review. The Water Institute at UNC,
Chapel Hill, NC, USA.
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who.int/taeniasis/disease/en/ (accessed 31 May 2018)
159
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Annex 1
SANITATION SYSTEM FACT
SHEETS
On-site sanitation systems
Fact sheet 1: Dry or ush toilet with on-site disposal
Fact sheet 2: Dry toilet or urine diverting dry toilet with on-site treatment in alternating pits or compost chamber
Fact sheet 3: Flush toilet with on-site treatment in twin pits
Fact sheet 4: Urine-diverting dry toilet with on-site treatment in dehydration vault
On-site systems with FSM and o-site treatment
Fact sheet 5: Dry or ush toilet with pit, euent inltration and o-site treatment of faecal sludge
Fact sheet 6: Flush (or urine-diverting ush) toilet with biogas reactor and o-site treatment
Fact sheet 7: Flush toilet with septic tank and euent inltration, and o-site faecal sludge treatment
Fact sheet 8: Urine-diverting dry toilet and container-based sanitation with o-site treatment of all contents
On-site systems with FSM, sewerage and o-site treatment
Fact sheet 9: Flush toilet with septic tank, sewerage and o-site treatment of faecal sludge and euent
O-site systems with sewerage and o-site treatment
Fact sheet 10: Flush toilet with sewerage and o-site wastewater treatment
Fact sheet 11: Urine-diverting ush toilet with sewerage and o-site wastewater treatment
Dry or pour ush toilet
Onsite disposal:
Fill and cover / Arborloo
Fact sheet 1
Dry or ush toilet with onsite disposal
Summary
This system is based on the use of a single pit technology
to collect and store excreta. The system can be used
with or without ushwater, depending on the toilet.
Inputs to the system can include urine, faeces, cleansing
water, ushwater and dry cleansing materials. The use
of ushwater, cleansing water and cleaning agents will
depend on water availability and local habit. The toilet
for this system can either be a dry toilet or a pour ush
toilet. A urinal could additionally be used. The toilet is
directly connected to a single pit or a single ventilated
improved pit (VIP) for containment. As the pit lls up, lea-
chate permeates from the pit into the surrounding soil.
When the pit is full, it can be backlled with soil and
a fruit or ornamental tree can be planted. The sludge
acts as a soil conditioner with the increase in organic
matter resulting in improved water holding capacity
and providing additional nutrients, which are slowly
reduced over time. A new pit has to be dug and this is
generally only possible when the existing superstruc-
ture is mobile.
Applicability
Suitability: This system should be chosen only where
there is enough space to continuously dig new pits. In
dense urban settlements, there is not sucient space
to continuously dig new pits.
Therefore, the system is best suited to rural and peri-ur-
ban areas where the soil is appropriate for digging pits
and absorbing the leachate; where hard, rocky ground
is found, or locations where groundwater level is high or
the soil is saturated are not suitable. It is also not suited
to areas that are prone to heavy rains or ooding, which
may cause pits to overow into users’ houses or to the
local community
2, 3
.
When it is not possible to dig a deep pit or the ground-
water level is too high, a shallow, raised pit can be a
viable alternative: the shallow pit can be extended by
building the pit upwards with the use of concrete rings
or blocks. A raised pit can also be constructed in an area
where ooding is frequent in order to keep water from
owing into the pit during heavy rain
4
.
Cost: This system is one of the least expensive to con-
struct in terms of capital cost and maintenance cost,
especially if the superstructure is mobile and can be
reused
2, 3
.
Design considerations
Toilet: The toilet should be made from concrete, bre-
glass, porcelain or stainless steel for ease of cleaning
and designed to prevent stormwater from inltrating
or entering the pit
2, 3
.
Containment: On average, solids accumulate at a rate
of 40 to 60L per person/year and up to 90L per person/
year if dry cleansing materials such as leaves or paper
are used. In many emergency situations, toilets with
inltrating pits are subjected to heavy use, and conse-
quently excreta and anal-cleansing materials are added
much faster than the decomposition rate; the ‘normal’
accumulation rates can therefore increase by 50%
4
.
The volume of the pit should be designed to contain
at least 1,000L. Typically, the pit is at least 3m deep and
1m in diameter. If the pit diameter exceeds 1.5m, there
is an increased risk of collapse. Depending on how
deep they are dug, some pits may last 20 or more years
without emptying, but a shallow pit may ll up within 6
to 12 months. As a general rule, a pit 3m deep and 1.5m
square will last a family of six about 15 years
3
.
Single pit or VIP
Toilet Containment
End use / disposal
160
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
The water table level, and groundwater use should be
taken into consideration in order to avoid contaminating
drinking water. If groundwater is not used for drinking
or alternative cost eective sources can be used, then
these options should be explored before assuming that
groundwater contamination by pit latrines is a problem.
Where groundwater is used for drinking and to prevent
its contamination, the bottom of the pit should be at
least 1.5m above the water table
3
. In addition, the pit
should be installed in areas located down gradient of
drinking water sources, and at a minimum horizontal
distance of 15m
5
.
Excreta, cleansing water, ushwater and dry cleansing
materials should be the only inputs to this system; other
inputs such as menstrual hygiene products and other
solid wastes are common and may contribute signif-
icantly to pit contents. As this will result in pits lling
Figure 1. A single pit latrine
Pit
Latrine slab above ground
level with hole, covered
when not in use
Mound of excavated soil
to seal pit lining and prevent
ooding of the pit by
surface water
Tight-tting lid
Latrine shelter designed
and built with appropriate
local materials
Air vent
Perforated lining to
allow leachate to percolate
into the soil
Gases escape
into the atmosphere
Solid residue
decomposes and
accumulates
The pit should be at least
2.0m deep and 1.0m wide,
and preferably round
The bottom of the pit should
be at least 1.5m above the
water table especially where
groundwater is used for
drinking
Source: WEDC
161
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
up more rapidly and make it more dicult to empty,
an appropriate container for disposal of these wastes
should be provided in the toilet cubicle. (Some grey-
water in the pit may help degradation, but excessive
amounts of greywater may lead to quick lling of the
pit and/or excessive leaching.)
End use/disposal: If the user plans to plant a tree in the
covered pit, then space and site conditions for the tree
when fully grown need to be taken into account. The
tree should not be planted in raw excreta but into the
soil lling on top of the pit contents
2
.
Operation and
maintenance considerations
Toilet and containment: The user is commonly respon-
sible for the construction of the toilet and pit, although
they may pay a mason to carry out the work. The user
will be responsible for cleaning and repairs to the toilet,
including the slab, seat/squat hole, drop-hole, cover/lid
and superstructure
2
.
To reduce smells and insect breeding, a cup of soil, ash
or sawdust is added to the pit after each defecation,
while periodically adding leaves will improve porosity
2
.
End use/disposal: As no emptying and transport is
required, once the pit is full the user is responsible
for digging a new pit and transferring the toilet and
superstructure, and then covering and lling the old pit
and, if required, planting a tree on top
2
.
There is little maintenance associated with a closed pit
other than taking care of the tree. Trees planted in aban-
doned pits require regular watering and a small fence
of sticks constructed around the sapling will protect it
from animals.
Mechanisms for protecting
public health
Toilet and containment : The toilet separates users from
excreta while the pit isolates the excreta and pathogens
within it from physical human contact.
During rains, the toilet and the pit contain the fresh
excreta and prevent it from being washed away into
surface water bodies
2, 3
.
End use/disposal: Users do not come in contact with
the faecal material and, thus, there is a very low risk
of pathogen transmission. The main mechanism for
pathogen reduction is through long storage time in
the pit. The conditions in the pit are not favourable for
pathogen survival, so over time, generally around one
to two years, the pathogens die o and the excreta
becomes safer. The die o period can be reduced by
adding lime or other alkaline material to raise the pH,
raising the temperature or reducing the moisture con-
tent. Ascaris (roundworm) eggs are the most persistent
pathogen to die o
6
.
Any leachate safely permeates into the surrounding soil
and pathogens contained in the liquid are ltered out,
adsorbed onto particles, or die o during their slow
travel through soil
2, 3
.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Brikké F, and Bredero M (2003). Linking Technology
Choice with Operation and Maintenance in the Context
of Community Water Supply and Sanitation. A refer-
ence document for planners and project sta. Geneva,
Switzerland.
3. Reed R A, Scott R E, and Shaw R J (2014). WEDC Guide
No. 25: Simple Pit Latrines. WEDC, Loughborough
University, UK.
4. Harvey P (2007). Excreta Disposal in Emergencies: A
Field Manual, WEDC, Loughborough University, UK.
5. Graham J, and Polizzotto M (2013). Pit latrines and
their impacts on groundwater quality: A systematic
review. Environmental Health Perspectives.
6. Stenström T A, Seidu R, Ekane N and Zurbrügg C
(2011). Microbial exposure and health assessments
in sanitation technologies and systems. Stockholm
Environment Institute (SEI).
162
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
Dry toilet or urine
diverting dry toilet
Pit humus or compost
used as a soil conditioner
Fact sheet 2
Dry toilet or urine-diverting dry toilet
(UDDT) with onsite treatment in alternating
pits or compost chamber
Summary
This system is designed to produce a solid, earthlike ma-
terial by using alternating pits or a composting chamber.
Inputs to the system can include urine, faeces, organics,
cleansing water, and dry cleansing materials. There is no
use of ushwater.
A dry toilet is the recommended toilet for this system,
although a urine-diverting dry toilet (UDDT) or a urinal
could also be used if the urine is highly valued for ap-
plication. A dry toilet does not require water to function
and in fact, water should not be put into this system;
cleansing water should be kept at a minimum or even
excluded if possible.
The dry toilet is directly connected to a double ventilated
improved pit (double VIP), fossa alterna or a composting
chamber for containment. Two alternating containers,
as in the double VIP or fossa alterna, give the material
an opportunity to drain, degrade, and transform into
pit humus (sometimes also called ecohumus), a nutri-
ent-rich, hygienically improved, humic material which
is safe to excavate.
When the rst pit is full, it is covered and temporarily
taken out of service. While the other pit is lling with
excreta (and potentially organics), the content of the
rst pit is allowed to rest and degrade for at least two
years before use. Only when both pits are full is the rst
pit emptied and put back into service. This cycle can be
indenitely repeated.
A composting container can also have alternating
chambers and, if properly operated, produces safe,
useable compost. For these reasons it is included in this
fact sheet.
This system is dierent from the system shown in Fact
sheet 5 regarding the treatment product generated at
the containment step. In the other system, the sludge re-
quires further treatment before it can be used, whereas
the pit humus or compost produced in this containment
technology is ready for end use and/or disposal.
Applicability
Suitability: Because the system is permanent and can
be indenitely used (as opposed to the single pits in
Fact sheet 1, which are backlled and covered), it can
be used where space is limited.
Additionally, because the treatment product must be
manually removed, this system is suitable for dense
areas that cannot be served by trucks for motorized
emptying. This system is especially appropriate for
water-scarce areas and where there is an opportunity
to use the compost or humic product as soil conditioner.
Cost: For the user, this system is one of the least ex-
pensive in terms of capital cost. The only maintenance
costs will be for cleaning of the toilet, upkeep of the
superstructure and arranging for periodic emptying of
containers
2, 3
; and it produces an end product that the
user may be able to use or sell.
Fossa alterna, double VIP
or compost chamber
Toilet Containment
End use / disposalConveyance
Manual emptying
and transport
163
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Design considerations
Toilet: The toilet should be made from concrete, bre-
glass, porcelain or stainless steel for ease of cleaning
and designed to prevent stormwater from inltrating
or entering the container
2, 3
.
Containment: For the pit-based technologies, the
water table level and groundwater use should be tak-
en into consideration in order to avoid contaminating
drinking water. If groundwater is not used for drinking
or alternative cost eective sources can be used, then
these options should be explored before assuming that
groundwater contamination by pit latrines is a problem.
Where groundwater is used for drinking and to prevent
its contamination, the bottom of the pit should be at
least 1.5m above the water table
3
. In addition, the pit
should be installed in areas located down gradient of
drinking water sources, and at a minimum horizontal
distance of 15m
4
.
Figure 1. A twin-pit latrine (fossa alterna)
Vent pipe
Fly screen
Pit 1
(not in use)
Pit 2
(in use)
Pit access
cover
Cubicle kept dark
to encourage ies to
seek light in the
vent pipe
Vent pipe
hole covered
Squat hole
covered
Source: WEDC
164
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
Excreta, cleansing water and dry cleansing materials can
usually be collected in the pit or chamber, especially
if they are carbon-rich (e.g., toilet paper, newsprint,
corncobs, etc.) as this may help degradation and airow.
Other inputs such as menstrual hygiene products and
other solid wastes are common and may contribute
signicantly to the contents. Where they cause the con-
tainer to ll up more rapidly and make it more dicult
to empty, an appropriate container for disposal of these
wastes should be provided in the toilet cubicle.
Greywater must be collected and treated separately.
Too much moisture in the container will ll the air voids
and deprive the microorganisms of oxygen, which may
impair the degradation process.
End use/disposal: As the excreta in the resting contain-
er is draining and degrading for at least two years, the
resulting pit humus or compost needs to be manually
removed using shovels (the material is too dry for mo-
torized emptying) and can be used in agriculture as a
soil conditioner
5
.
Operation and
maintenance considerations
Toilet and containment: The user is commonly respon-
sible for the construction of the toilet and container,
although they may pay a mason to carry out the work.
The user will be responsible for cleaning of the toilet and
are most likely to be responsible for removing the pit
humus or compost, although they may pay a labourer
or service provider to do this.
At shared facilities, a person (or persons) to clean and
carry out other maintenance tasks (e.g. repairs to super-
structure) on behalf of all users needs to be identied.
The success of this system depends on proper oper-
ation and an extended storage period. If a suitable
and continuous source of soil, ash or organics (leaves,
grass clippings, coconut or rice husks, woodchips, etc.)
is available, the decomposition process is enhanced
and the storage period can be reduced. The required
storage time can be minimized if the material remains
well aerated and not too moist.
End use/disposal: The material removed from the con-
tainer or compost chamber should be in a safe, useable
form, although workers must wear appropriate personal
protection during removal, transport and end use.
Mechanisms for protecting
public health
Toilet and containment: The toilet separates users
from excreta and the container isolates the excreta and
pathogens within from physical human contact.
The main mechanism for pathogen reduction is through
long storage time. The conditions in the pit are not fa-
vourable for pathogens survival, which die o over time.
In the pit, any leachate permeates into the surrounding
soil and pathogens contained in the liquid are ltered
out, adsorbed onto particles, or die o during their slow
travel through soil
2, 3
.
During rains, the slab and the pit or composting cham-
ber contain the fresh excreta and prevent it from being
washed away into surface water bodies, while squat-
hole covers or lids can reduce disease transmission by
preventing disease carrying vectors from entering and
leaving the pit
2, 3
.
Conveyance: Any non-degradable solid waste removed
from the container needs to be disposed of properly, for
example through a regulated solid waste management
service or, where this is not available, through burial.
End use/disposal: Since it has undergone signicant
degradation, the pit humus or compost is quite safe
to handle and use as a soil conditioner in agriculture. If
there are concerns about the pathogen level or quality
of the pit humus or compost, it can be further compost-
ed in a dedicated composting facility before it is used.
If there is no end use for the treatment product, it can
be permanently disposed of.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Brikké F, and Bredero M (2003). Linking Technology
Choice with Operation and Maintenance in the Context
of Community Water Supply and Sanitation. A refer-
ence document for planners and project sta. Geneva,
Switzerland.
3. Reed R A, Scott R E, and Shaw R J (2014). WEDC Guide
No. 25: Simple Pit Latrines. WEDC, Loughborough
University, UK.
4. Graham J, and Polizzotto M (2013). Pit latrines and
their impacts on groundwater quality: A systematic
review. Environmental Health Perspectives.
5. Strande L (2017). Introduction to Faecal Sludge
Management. Online Course available at: www.
sandec.ch/fsm_tools (accessed March 2017). Sandec:
Department of Sanitation, Water and Solid Waste
for Development Eawag: Swiss Federal Institute of
Aquatic Science and Technology.
165
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Pour ush toilet
(squat pan or pedestal)
Pit humus or compost
used as a soil conditioner.
No euent product.
Twin pits for pour ush
Toilet Containment
End use / disposalConveyance
Manual emptying
and transport
Fact sheet 3
Flush toilet with onsite treatment in twin pits
Summary
This is a water-based system utilizing the pour ush
toilet (squat pan or pedestal) and twin pits to produce
a partially digested, humus-like product, that can be
used as a soil conditioner.
Inputs to the system can include faeces, urine, ush-
water, cleansing water, dry cleansing materials and
greywater. The toilet technology for this system is a
pour ush toilet. A urinal could additionally be used.
The blackwater output from the pour ush toilet (and
possibly greywater) is discharged into twin pits for
containment.
The twin pits are lined with a porous material, allowing
the liquid to inltrate into the ground while solids ac-
cumulate and degrade at the bottom of the pit. While
one pit is lling with blackwater, the other pit remains
out of service. When the rst pit is full, it is covered
and temporarily taken out of service. It should take a
minimum of two years to ll a pit. When the second pit
is full, the rst pit is re-opened and emptied.
After a resting time of at least two years, the content
is transformed into pit humus (sometimes also called
ecohumus), a nutrient-rich, safer, humic material which
is safe to excavate for end use as a soil conditioner, or
disposal. The emptied pit is then put back into opera-
tion. This cycle can be indenitely repeated.
Applicability
Suitability: This system is suited to rural and peri-urban
areas with appropriate soil that can continually and
adequately absorb the leachate. It is not appropriate
for areas with clayey or densely packed soil. This system
is well-suited for cleansing with water. If possible, dry
cleansing materials should be collected and disposed
of separately because they may clog the pipe ttings
and prevent the liquid inside the pit from inltrating
into the soil.
Cost: For the user, this system is one of the least ex-
pensive in terms of capital cost. The only maintenance
costs will be for cleaning of the toilet, upkeep of the
superstructure and arranging for periodic emptying of
containers
2, 3
; and it produces an end product that the
user may be able to use or sell.
Design considerations
Toilet: The squat pan or pedestal should be made from
concrete, breglass, porcelain or stainless steel for ease
of cleaning and designed to prevent stormwater from
inltrating or entering the pit
2, 3
.
Containment: As leachate from twin pits directly inl-
trates the surrounding soil, this system should only be
installed where there is a low groundwater table. If there
is frequent ooding or the groundwater table is too
high and enters the twin pits, the dewatering process,
particularly in the resting pit, will be hindered.
Greywater can be co-managed along with the blackwa-
ter in the twin pits, especially if the greywater quantities
are relatively small, and no other management system
is in place to control it.
However, the water table level and groundwater use
should be taken into consideration in order to avoid
contaminating drinking water. If groundwater is not
used for drinking or alternative cost eective sources
can be used, then these options should be explored
before assuming that groundwater contamination by
pit latrines is a problem. Where groundwater is used for
166
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
drinking and to prevent its contamination, the bottom of
the pit should be at least 1.5m
3
above the water table.
In addition, the pit should be installed in areas located
down gradient of drinking water sources, and at a min-
imum horizontal distance of 15m
4
.
End use/disposal: Any non-degradable solid waste re-
moved from the pit, needs to be disposed of properly, for
example through a regulated solid waste management
service or, where this is not available, through burial.
Operation and
maintenance considerations
Toilet and containment: The user is commonly respon-
sible for the construction of the toilet and pit, although
they may pay a mason to carry out the work.
The user will be responsible for cleaning of the toilet
and are most likely to be responsible for removing the
pit humus, although they may pay a labourer or service
provider to do this
2
.
Figure 1. A twin-pit, pour ush latrine
Side view
Pit 1
not in use
Handles for pit and
inspection chamber covers
Top view
Pit 2
in use
Inspection chamber with stone or block
of wood for blocking secondary pipe
At least 1m
Water trap
(if tted)
Connecting pipe
Pan
Inspection chamber
At least 1m
Source: WEDC
167
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
At shared facilities, a person (or persons) to clean and
carry out other maintenance tasks (e.g. repairs to super-
structure) on behalf of all users needs to be identied.
End use/disposal: As the excreta in the resting pit
is draining and degrading for at least two years, the
resulting pit humus needs to be manually removed
using shovels – vacuum truck access to the pits is not
necessary.
The pit humus removed should be in a safe, useable
form, although workers must wear appropriate personal
protection during removal, transport and end use.
Mechanisms for protecting
public health
Toilet and containment: The toilet separates users
from excreta and the pit isolates the excreta and path-
ogens within it from physical human contact.
The main mechanism for pathogen reduction is through
long storage time. The conditions in the pit are not fa-
vourable for pathogen survival, which die o over time.
Leachate permeates from the pit into the surrounding
soil and pathogens contained in the liquid are ltered
out, adsorbed onto particles, or die o during their slow
travel through soil.
During rains, the toilet and the pit contain fresh excreta
and prevent it from being washed away into surface
water bodies, while squat-hole covers or lids can reduce
disease transmission by preventing disease carrying
vectors from entering and leaving the pit
2, 3
.
Treatment: Since it has undergone signicant dewa-
tering and degradation, pit humus is much safer than
raw, undigested sludge. Therefore, it does not require
further treatment in an osite treatment facility. If there
are concerns about the pathogen level or quality of the
pit humus, it can be further composted in a dedicated
composting facility before it is used (see Fact sheet 5).
End use/disposal: Pit humus has good soil conditioning
properties and can be applied in agriculture
5
. If there
is no end use for the product, it can be permanently
disposed of.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Brikké F, and Bredero M (2003). Linking Technology
Choice with Operation and Maintenance in the Context
of Community Water Supply and Sanitation. A refer-
ence document for planners and project sta. Geneva,
Switzerland.
3. Reed R A, Scott R E, and Shaw R J (2014). WEDC Guide
No. 25: Simple Pit Latrines. WEDC, Loughborough
University, UK.
4. Graham J, and Polizzotto M (2013). Pit latrines and
their impacts on groundwater quality: A systematic
review. Environmental Health Perspectives.
5. Strande L (2017). Introduction to Faecal Sludge
Management. Online Course available at: www.
sandec.ch/fsm_tools (accessed March 2017). Sandec:
Department of Sanitation, Water and Solid Waste
for Development Eawag: Swiss Federal Institute of
Aquatic Science and Technology.
168
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
Urine:
Jerry cans or tanks
Urine-diverting
dry toilet
Dried faeces:
Used as a soil conditioner
Fact sheet 4
Urine-diverting dry toilet (UDDT) with
onsite treatment in dehydration vault
Summary
This system is designed to separate urine and faeces to
allow the faeces to dehydrate and/or recover the urine
for benecial use. Inputs to the system can include fae-
ces, urine, cleansing water and dry cleansing materials.
The main toilet technology for this system is a urine-di-
verting dry toilet (UDDT), which allows urine and faeces
to be separately stored. A urinal can additionally be
installed for the eective storage of urine. UDDT designs
vary and include adaptations for dierent preferences,
for instance with a third diversion for cleansing wa-
ter management.
Dehydration vaults are used for the containment
of faeces. They should be kept as dry as possible to
encourage dehydration and pathogen reduction. After
each use, the faeces are covered with ash, lime, soil, or
sawdust, which helps to absorb humidity, minimize
odours and provide a barrier between the faeces and
potential disease carrying vectors. The vaults should be
watertight and care should be taken to ensure that no
water is introduced – cleansing water should never be
put into dehydration vaults.
Using two dehydration vaults, and alternating their use,
allows for an extended dehydration period so that when
they are removed the dried faeces contain zero, or very
low, pathogen levels and pose little human health risk. A
minimum storage time of six months is recommended
when ash or lime are used as cover material, after which
the dried faeces can be applied as soil conditioner
2
.
The urine can be stored in either jerrycans or a tank for
application in agriculture. With its high nutrient content
it can be used as a good liquid soil fertilizer and can be
easily handled and poses little risk because it is nearly
sterile. Stored urine can be transported using manual
or motorized transport technologies. Alternatively,
the urine can be diverted directly to the ground for
inltration through a soak pit.
Applicability
Suitability: This system can be used anywhere, but is
especially appropriate for rocky areas where digging
is dicult, where there is a high groundwater table,
Faeces:
Dyhydration vault
Toilet Containment
End use / disposalConveyance
Dried faeces:
Manual emptying
and manual or motorized transport
Urine:
Applied to elds as a
liquid soil fertilizer
Urine:
Manual or motorized transport
169
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Key: Urine collection Faeces collection Anal cleansing unit
Anal cleansing
method: wiping
Anal cleansing
method: wiping
Anal cleansing
method: washing
or in water-scarce regions. A dry, hot climate can also
considerably contribute to the rapid dehydration of the
faeces.
If there is no agricultural need and/or no acceptance of
using the urine, it can be directly inltrated into the soil
or into a soak pit.
Cost: For the user, this system is one of the least
expensive in terms of capital cost and produces end
products that the user may be able to use or sell. As
the containment technology does not include a pit or
underground tank, there is no excavation cost, however,
this saving may be oset by the cost of constructing
the above ground tank or vault and urine separation
arrangement, which will also require a reasonable level
of technical expertise.
The only maintenance costs will include cleaning of the
toilet, upkeep of the superstructure and arranging for
periodic emptying of the vaults and urine containers
(if any).
Design considerations
Toilet: The toilet should be made from concrete, bre-
glass, porcelain or stainless steel for ease of cleaning
and designed to prevent stormwater from inltrating
or entering the vaults. Where there are no suppliers
of prefabricated UDDT pedestals or slabs, they can be
locally manufactured using available materials.
Containment: The dehydration vaults should be wa-
tertight and tted with a vent pipe to reduce nuisance
from smells and preventing access to disease carrying
vectors. Any urine tanks should also be watertight and
sealed to reduce nuisance from smells.
All types of dry cleansing materials can be used,
although it is best to collect them separately as they
will not decompose in the vaults and use up space.
Cleansing water must be separated from the faeces,
but it can be mixed with the urine if it is transferred
to a soak pit. If urine is used in agriculture, cleansing
water should be kept separate and inltrated locally
or treated along with greywater. A separate greywater
system is required since it should not be introduced
into the dehydration vaults.
Conveyance: Manual emptying equipment is required
for the removal of the dried faeces generated from the
dehydration vaults (the material is too dry for motor-
ized emptying), which can then be transported using
manual or motorized transport, and used in agriculture
as a soil conditioner.
Operation and
maintenance considerations
Toilet /containment: The user is commonly responsible
for the construction of the UDDT, dehydration vaults
and providing the urine tanks (if any), although they
may pay a mason to carry out the work. The user will
be responsible for cleaning of the UDDT and are most
Figure 1. Urine diversion systems
Source: WEDC
170
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
likely to be responsible for removing the dried faeces,
although they may pay a labourer or service provider
to do this.
At shared facilities, a person (or persons) to clean and
carry out other maintenance tasks (e.g. repairs to super-
structure) on behalf of all users needs to be identied.
The success of this system depends on the ecient
separation of urine and faeces, as well as the use of a
suitable cover material. Therefore, the urine separation
plumbing must be kept free of blockages to prevent
urine from backing up and overowing into the dehy-
dration vaults, and there should be a constant supply of
ash, lime, soil, or sawdust available to cover the faeces.
End use/disposal: The dried faeces removed from the
container should be in a safe, useable form with a zero to
very low pathogen content, although workers would be
advised to wear appropriate personal protection during
removal, transport and end use.
Mechanisms for protecting
public health
The toilet separates users from excreta and the dehy-
dration vault isolates the excreta and pathogens within
from physical human contact.
The main mechanism for pathogen reduction in the
vaults is through long storage time. The dehydrated
conditions in the vault are not favourable for pathogen
survival, which die o over time. If ash or lime is used as
a cover material, the related pH increase also helps to kill
pathogens. The urine poses little health risk as it is nearly
sterile, and storage before use in sealed containers or
disposal to the ground via a soak pit will protect public
health. However, in areas in which schistosomiasis is
endemic, urine should not be used in water-based
agriculture, such as rice paddies.
During rains, the slab and vaults contain the fresh
excreta and prevent it from being washed away into
surface water bodies, while squat-hole covers or lids and
a screened vent pipe can reduce disease transmission
by preventing disease carrying vectors from entering
and leaving the vaults.
Any non-degradable solid waste removed from the
vaults needs to be disposed of properly, for example
through a regulated solid waste management service
or, where this is not available, through burial.
Since it has undergone signicant degradation, the
dried faeces should be safe for end use as a soil con-
ditioner in agriculture. If there are concerns about the
pathogen level or quality of the dried faeces, they can
be further composted in a dedicated composting facility
before it is used.
References
The text for this fact sheet is based on Tilley, et al.
1
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Stenström T A, Seidu R, Ekane N and Zurbrügg C
(2011). Microbial exposure and health assessments
in sanitation technologies and systems. Stockholm
Environment Institute (SEI).
171
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Fact sheet 5
Dry or ush toilet with pit, euent inltration
and osite treatment of faecal sludge
Summary
This system is similar to the system described in Fact
sheet 1 with the use of a single pit technology to col-
lect and store excreta. The system can be used with or
without ushwater, depending on the toilet. Inputs to
the system can include urine, faeces, cleansing water,
flushwater and dry cleansing materials. The use of
ushwater and/or cleansing water will depend on water
availability and local habit.
The toilet for this system can either be a dry toilet or a
pour ush toilet. A urinal could additionally be used.
The toilet is directly connected to a single pit or a single
ventilated improved pit (VIP). As the pit lls up, leachate
permeates from the pit into the surrounding soil.
When the pit is full the faecal sludge needs to be
emptied and transported for treatment. The treatment
products can then be used (e.g. euent used in irri-
gation), converted into end use products (e.g. faecal
sludge converted to soil conditioner or solid fuels) or
disposed of.
Applicability
Suitability: This system should be chosen only when
there is an appropriate way to empty, transport, treat
and use or dispose of the faecal sludge. For instance,
in dense urban settlements, narrow roads may make it
dicult for vehicles with emptying equipment to gain
access to pits.
It is suited to areas where the soil is appropriate for
digging pits and absorbing the leachate; where hard,
rocky ground is found, or where groundwater level is
high or the soil is saturated, conditions are not suitable.
It is also not suited to areas that are prone to heavy rains
or ooding, which may cause pits to overow into users’
houses or to the local community
2, 3
.
When it is not possible to dig a deep pit or the ground-
water level is too high, a raised pit can be a viable
alternative: the shallow pit can be extended by building
the pit upwards with the use of concrete rings or blocks.
A raised pit can also be constructed in an area where
ooding is frequent in order to keep water from owing
into the pit during heavy rain.
Cost: For the user, this system is one of the least expen-
sive in terms of capital cost. However, the maintenance
costs may be considerable, depending on the frequency
and method of pit emptying
2, 3
.
The capital cost of the treatment plant may also be
considerable, while the treatment plant maintenance
costs will depend on the technology chosen and the
energy required to operate it.
Design considerations
Toilet: The toilet should be made from concrete, bre-
glass, porcelain or stainless steel for ease of cleaning
and designed to prevent stormwater from inltrating
or entering the pit
2, 3
.
Containment: On average, solids accumulate at a rate
of 40 to 60L per person/year and up to 90L per person/
year if dry cleansing materials such as leaves or paper
are used. In many emergency situations, toilets with
inltrating pits are subjected to heavy use, consequently
Dry or pour ush
Manual emptying
and transport
Faecal sludge
treatment plant for
sludge and euent
Single pit or single VIP
Soil conditioner; solid fuel;
building materials;
irrigation; surface water
recharge
*
Toilet
Conveyance Treatment End use / disposalContainment
* Sludge: treated and used as soil conditioner, solid fuel or building materials. Euent: treated and used for irrigation or surface water recharge.
172
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
excreta and anal-cleansing materials are added much
faster than the decomposition rate, therefore the ‘nor-
mal’ accumulation rates can increase by 50 percent
9
.
The volume of the pit should be designed to contain
at least 1,000L. Typically, the pit is at least 3m deep
and around 1m in diameter. If the pit diameter exceeds
1.5m, there is an increased risk of collapse. Depending
on usage and how deep they are dug, some pits may
last 20 or more years without emptying, but shallow pits
that are used by many people every day may require
emptying once or twice a year. As a general rule, a pit
3m deep and 1.5m wide that is used by a family of six,
will require emptying after about 15 years
3
.
As the pit will be reused, it should be lined. Pit lining
materials can include brick, rot-resistant timber, con-
crete, stones, or mortar plastered onto the soil. If the
soil is stable (i.e., no presence of sand or gravel deposits
or loose organic materials), the whole pit need not be
lined. The bottom of the pit should remain unlined to
allow for the inltration of liquids out of the pit.
The water table level and groundwater use should be
taken into consideration in order to avoid contaminating
drinking water. If groundwater is not used for drinking
or alternative cost eective sources can be used, then
these options should be explored before assuming that
groundwater contamination by pit latrines is a problem.
Where groundwater is used for drinking and to prevent
its contamination, the bottom of the pit should be at
least 1.5m above the water table
3
. In addition, the pit
should be installed in areas located down gradient of
drinking water sources, and at a minimum horizontal
distance of 15m
4
.
Excreta, cleansing water, ushwater and dry cleansing
materials should be the only inputs to this system;
other inputs such as menstrual hygiene products and
other solid wastes are common and may contribute
signicantly to pit contents. As this will result in pits
lling up more rapidly and make it more dicult to
empty, an appropriate container for disposal of these
wastes should be provided in the toilet cubicle. (Some
greywater in the pit may help degradation, but excessive
amounts of greywater may lead to quick lling of the pit
and/or excessive leaching.)
Conveyance: As the untreated faecal sludge is full
of pathogens, human contact and direct agricultural
application should be avoided. Instead, the emptied
sludge should be transported to a faecal sludge treat-
ment facility.
The conveyance technologies that can be used include
manual emptying and transport or motorized emptying
and transport. However, a vacuum truck cannot be used
as it can only empty liquid faecal sludge.
In the event that a treatment facility is not easily acces-
sible, the faecal sludge can be discharged to a transfer
station. From there, it can be transported to the treat-
ment facility by a motorized transport technology.
Treatment: Treatment technologies produce both
euent and sludge, which may require further treatment
prior to end use and/or disposal. For example, euent
from a faecal sludge treatment facility could be co-
treated with wastewater in waste stabilization ponds
or in constructed wetlands, and then used for irrigation
water, sh ponds, oating plant ponds or discharged to
a surface water body or to groundwater.
End use/disposal: Options for the end use of the
treated sludge include use in agriculture as a soil condi-
tioner or as a solid fuel or as an additive to construction
materials
6
.
Operation and
maintenance considerations
Toilet and containment: The user is commonly
responsible for the construction of the toilet and pit,
although they may pay a mason to carry out the work.
The user will be responsible for cleaning and repairs to
the toilet, including the slab, seat/squat hole, drop-hole,
cover/lid and superstructure. In rural areas, the user may
undertake emptying but in urban locations this is more
likely to be done by a service provider who charges the
household for the service
2
.
At shared facilities, a person (or persons) needs to be
identied to clean and carry out maintenance tasks on
behalf of all users.
Conveyance and treatment: The conveyance and
treatment technologies are typically operated and
maintained by a combination of private and public
service providers working together; for example,
where emptying and transport is done by private and/
or public service providers who deliver faecal sludge to
treatment plants operated by public service providers.
All plant, tools and equipment used in the conveyance
and treatment steps will require regular maintenance
by the relevant service providers.
End use/disposal: Farmers and the general public will
be the main users of the treatment products and will be
responsible for maintenance of all tools and equipment
they use
5
.
Mechanisms for protecting
public health
Toilet and containment: The toilet separates users from
excreta while the pit isolates the excreta and pathogens
within from physical human contact.
During rains, the toilet and the pit contain the fresh
excreta and prevent it from being washed away into
173
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
surface water bodies, while squat-hole covers or lids
can reduce disease transmission by preventing disease
carrying vectors from entering and leaving the pit
2, 3
.
Any leachate permeates from the pit into the surround-
ing soil and pathogens contained in the liquid are
ltered out, adsorbed onto particles, or die o during
their slow travel through soil
2, 3
.
Conveyance: The conveyance step removes the
pathogen hazard from the neighbourhood or local
community. To do this safely, emptying and transport
workers require personal protective equipment as well
as standard operating procedures. For instance, the
wearing of boots, gloves, masks and clothing that cover
the whole body is essential, as well as washing facilities
and good hygiene practices. The emptiers should not
enter a pit but use long handled shovels to remove
sludge at the bottom of a pit
5
.
Any non-degradable solid waste removed from the pit,
needs to be disposed of properly, for example through
a regulated solid waste management service or, where
this is not available, through burial.
Treatment: In order to reduce the risk of exposure of the
local community, all treatment plants must be securely
fenced to prevent people entering the site. To safeguard
workers’ health when operating the plant and carrying
out maintenance to tools and equipment, all treatment
plant workers must wear appropriate protective equip-
ment and follow standard operating procedures
5
.
End use/disposal: If correctly designed, constructed
and operated, treatment technologies can be combined
to reduce the pathogen hazard within the euent or
sludge by removal, reduction or inactivation to a level
appropriate for the intended end use and/or disposal
practice
8
. For example, sludges require dewatering and
drying followed by co-composting with organics before
use as a compost-type soil conditioner, but for use as a
solid fuel or building material additive, they only require
dewatering and drying. While euent will require stabi-
lization and pathogen inactivation in a series of ponds
or wetlands before use as crop irrigation water
6, 7
.
To protect the health of themselves, colleagues and
the general public, end users must wear appropriate
protective equipment and follow standard operating
procedures in accordance with the actual level of treat-
ment and end use
5
.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Brikké F, and Bredero M (2003). Linking Technology
Choice with Operation and Maintenance in the Context
of Community Water Supply and Sanitation. A refer-
ence document for planners and project sta. Geneva,
Switzerland.
3. Reed R A, Scott R E, and Shaw R J (2014). WEDC Guide
No. 25: Simple Pit Latrines. WEDC, Loughborough
University, UK.
4. Graham J, and Polizzotto M (2013). Pit latrines and
their impacts on groundwater quality: A systematic
review. Environmental Health Perspectives.
5. World Health Organization (2015). Sanitation Safety
Planning – Manual for safe use and disposal of waste-
water, greywater and excreta. Geneva, Switzerland.
6. Strande L (2017). Introduction to Faecal Sludge
Management. Online Course available at: www.
sandec.ch/fsm_tools (accessed March 2017). Sandec:
Department of Sanitation, Water and Solid Waste
for Development Eawag: Swiss Federal Institute of
Aquatic Science and Technology.
7. World Health Organization (2006). WHO Guidelines
for the safe use of wastewater, excreta and greywater.
Volumes I to IV. World Health Organization, Geneva,
Switzerland.
8. Stenström T A, Seidu R, Ekane N and Zurbrügg C
(2011). Microbial exposure and health assessments
in sanitation technologies and systems. Stockholm
Environment Institute (SEI).
174
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
Fact sheet 6
Flush (or urine-diverting ush) toilet with
biogas reactor and osite treatment
Summary
This system is based on the use of a biogas reactor to
collect, store and treat the excreta. Additionally, the bi-
ogas reactor produces biogas, which can be burned for
cooking, lighting or electricity generation. Inputs to the
system can include urine, faeces, ushwater, cleansing
water, dry cleansing materials, organics (e.g., market or
kitchen waste) and, if available, animal waste.
The system requires a pour ush toilet or, if there is
a demand for the urine to be used in agriculture, a
urine-diverting ush toilet. A urinal could additionally
be used. The toilet is directly connected to a biogas
reactor, which is also known as an anaerobic digester. If
a urine-diverting ush toilet is installed (and/or a urinal),
it will be connected to a storage tank or jerry cans for
urine storage.
Although the sludge has undergone anaerobic diges-
tion, it is not pathogen free and must be removed with
caution and transported for further treatment, where
it will produce both euent and sludge. Depending
on the end use, these fractions may require further
treatment prior to end use and/ or disposal.
The biogas produced must be constantly used, for
example as a clean fuel for cooking or for lighting. If
the gas is not burned, it will accumulate in the tank
and, with increasing pressure, will push out the partially
digested sludge (digestate) until the biogas escapes to
the atmosphere through the digestate outlet.
A biogas reactor can work with or without urine. The
advantage of diverting urine from the reactor is that
it can be used separately as a concentrated nutrient
source without high pathogen contamination (see Fact
sheet 4 for more details).
Applicability
Suitability: This system is best suited to rural and
peri-urban areas where there is appropriate space, a
regular source of organic substrate for the biogas reac-
tor and a use for the partially digested sludge (digestate)
and biogas.
The reactor itself can be built underground (e.g., under
agricultural land, and in some cases roads) and, there-
Pour ush or cistern ush
or urine-diverting ush
toilet
Pipework for
conveyance of biogas
N/A
Biogas reactor or
anaerobic digester
Biogas: used as liquid fuel
for cooking, lighting or
electricity generation
Toilet
Conveyance Treatment End use / disposalContainment
Motorized emptying
and transport of partially
digested liquid sludge
(digestate)
Treatment plant for
sludge and euent
Soil conditioner; solid fuel;
building materials;
irrigation; surface water
recharge
*
* Sludge: treated and used as soil conditioner, solid fuel or building materials. Euent: treated and used for irrigation or surface water recharge.
175
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
fore, does not require a lot of space. Although a reactor
may be feasible in a dense urban area, proper sludge
management is essential as the digestate production
is continuous and requires year-round emptying and
transport away from the site.
Cost: For the user, the capital investment for this system
is considerable (excavation and installation of a biogas
tank), but several households can share the costs if the
system is designed for a larger number of users. The
maintenance costs may be considerable, depending
on the frequency and method of biogas tank emptying
2, 3
. However, these costs are somewhat oset by the
generation of a constant supply of liquid fuel.
The capital cost of the treatment plant may also be
considerable, while the treatment plant maintenance
costs will depend on the technology chosen and the
energy required to operate it.
Design considerations
Toilet: The toilet should be made from concrete, bre-
glass, porcelain or stainless steel for ease of cleaning
and designed to prevent stormwater from inltrating
or entering the biogas reactor
2, 3
.
Containment: The biogas reactor can function with a
large range of inputs and is especially suitable where a
constant source of animal manure is available, or where
market and kitchen waste is abundant
4
. On farms, for
example, large quantities of biogas can be produced
if animal manure is co-digested with the blackwater,
whereas significant gas production would not be
achieved from human excreta alone. Wood material or
straw are dicult to degrade and should be avoided
in the substrate. Achieving a good balance between
excreta (both human and animal), organics and water
can take some time, though the system is generally
forgiving.
Most types of dry cleansing materials and organics
can be discharged into the biogas reactor, although
to accelerate digestion and ensure even reactions
within the tank, large items should be broken or cut
into small pieces.
However, care should be taken not to overload the
system with either too many solids or too much liquid.
For example, greywater should not be added into the
biogas reactor as it substantially reduces the hydraulic
retention time; a separate greywater system is there-
fore required.
Conveyance: As the digestate is not pathogen free,
human contact and direct agricultural application
should be avoided
4
. Instead, it should be transported
to a dedicated sludge treatment facility. The conveyance
technologies that can be used include both manual or
motorized emptying and transport. In the event that a
treatment facility is not easily accessible, the sludge can
be discharged to a transfer station. From the transfer
station it is then transported to the treatment facility
by a motorized transport technology.
Treatment: Treatment technologies produce both
euent and sludge, which may require further treat-
ment prior to end use and/or disposal. For example,
euent from a faecal sludge treatment facility could
be co-treated with wastewater in waste stabilization
ponds or in constructed wetlands.
End use/disposal: Options for the end use and/or
disposal of the treated euent include irrigation, sh
ponds, oating plant ponds or discharge to a surface
water body or to groundwater. Treated sludge can either
be used in agriculture as a soil conditioner as a solid fuel
or as an additive to construction materials
5
.
Operation and
maintenance considerations
Toilet and containment: The user is responsible for
the construction of the toilet and the biogas reactor,
but they are most likely to pay a mason to carry out
the work. The user will be responsible for cleaning of
the toilet and employing an emptying service provider
to empty digestate from the biogas tank periodically.
At shared facilities, a person (or persons) to clean and
carry out other maintenance tasks (e.g. repairs to super-
structure) on behalf of all users needs to be identied
as well as an emptying service provider.
Biogas can be safely burned for cooking, lighting or
electricity generation but as it is explosive when mixed
with air, precautions should be taken when a reactor is
opened for cleaning, when biogas is released to repair a
reactor, or when there is a gas leak in a poorly ventilated
room. In such cases, sparks, smoking and open ames
should be avoided.
Conveyance, treatment and end use/disposal: The
digestate conveyance and treatment part of the system
is typically operated and maintained by a combination
of private and public service providers working togeth-
er; for example, emptying and transport may be done
by private and/or public service providers who deliver
the digestate to treatment plants operated by public
service providers.
Importantly, for this system, all machinery, tools and
equipment used in the conveyance, treatment and end
use/disposal steps will require regular maintenance by
the service providers.
Mechanisms for protecting
public health
Toilet and containment: The toilet separates users from
excreta and the biogas tank isolates the brownwater
and pathogens within it from physical human contact.
176
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
During rains, the slab and the impermeable biogas
tank contain the fresh excreta and prevent it from be-
ing washed away into surface water bodies, while the
water seal reduces disease transmission by preventing
disease carrying vectors from entering and leaving the
biogas tank.
Conveyance: The conveyance step removes the path-
ogen containing digestate from the neighbourhood
or local community to a treatment plant. Motorized
emptying using vacuum trucks (or similar) tted with
long-reach hoses is the preferred method, as this
reduces direct contact by emptiers with the sludge.
Nevertheless, emptying and transport workers must
wear personal protective equipment and follow stand-
ard operating procedures. For instance, the wearing of
boots, gloves, masks and clothing that cover the whole
body is essential, as well as washing facilities and good
hygiene practices. The emptiers should not enter a
biogas tank but use long handled shovels to remove
any hard to shift sludge at the bottom
6.
Treatment: If correctly designed, constructed and
operated, treatment technologies can be combined
to reduce the pathogen hazard within the euent or
sludge by removal, reduction or inactivation to a level
appropriate for the intended end use and/or disposal
practise. For example, sludges require dewatering and
drying followed by co-composting with organics before
use as a compost-type soil conditioner, but for use as a
solid fuel or building material additive, they only require
dewatering and drying. Euent will require stabilization
and pathogen inactivation in a series of ponds or wet-
lands before use as crop irrigation water.
In order to reduce the risk of exposure of the local com-
munity, all treatment plants must be securely fenced to
prevent people entering the site; to safeguard workers’
health when operating the plant and carrying out main-
tenance to tools and equipment, all treatment plant
workers must wear appropriate protective equipment
and follow standard procedures
6
.
End use/disposal: Provided the workers responsible
for operation and maintenance of the biogas reactor
follow standard operating procedures, the burning of
biogas presents no health risk to the consumers of end
products generated using biogas
4
.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Brikké F, and Bredero M (2003). Linking Technology
Choice with Operation and Maintenance in the Context
of Community Water Supply and Sanitation. A refer-
ence document for planners and project sta. Geneva,
Switzerland.
3. Reed R A, Scott R E, and Shaw R J (2014). WEDC Guide
No. 25: Simple Pit Latrines. WEDC, Loughborough
University, UK.
4. Stenström T A, Seidu R, Ekane N and Zurbrügg C
(2011). Microbial exposure and health assessments
in sanitation technologies and systems. Stockholm
Environment Institute (SEI).
5. Strande L (2017). Introduction to Faecal Sludge
Management. Online Course available at: www.
sandec.ch/fsm_tools (accessed March 2017). Sandec:
Department of Sanitation, Water and Solid Waste
for Development Eawag: Swiss Federal Institute of
Aquatic Science and Technology.
6. World Health Organization (2015). Sanitation Safety
Planning – Manual for safe use and disposal of waste-
water, greywater and excreta. Geneva, Switzerland.
177
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Fact sheet 7
Flush toilet with septic tank and euent
inltration, and osite faecal sludge treatment
Summary
This is a water-based system that requires a ush toilet
and a containment technology that is appropriate for
receiving large quantities of water. Inputs to the system
can include faeces, urine, ushwater, cleansing water,
dry cleansing materials and greywater.
Two toilet technologies can be used for this system: a
pour ush toilet or a cistern ush toilet. A urinal could
additionally be used. The toilet is directly connected to a
containment technology for the blackwater generated:
either a septic tank, an anaerobic baed reactor (ABR),
or an anaerobic lter may be used.
The anaerobic processes reduce the organic and path-
ogen load, but the euent is still not suitable for direct
use; instead, it can be directly diverted to the ground for
disposal through a soak pit or a leach eld.
The sludge that is generated from the containment
technology is also not pathogen free and must be
removed with caution and transported for further treat-
ment, where it will produce both euent and sludge.
Depending on the end use, these fractions may require
further treatment prior to end use and/or disposal.
Applicability
Suitability: This system is only appropriate in areas
where desludging services are available and aordable
and where there is an appropriate way to dispose of
the sludge.
For the soak pit or leach eld (the inltration technolo-
gies) to work, there must be sucient available space
and the soil must have a suitable capacity to absorb the
euent. If this is not the case, refer to Fact sheet 9 (Flush
toilet with septic tank, sewerage and osite treatment
of faecal sludge and euent).
This system can be adapted for use in colder climates,
even where there is ground frost.
The system requires a constant source of water for
toilet ushing.
Cost: For the user, the capital investment for this system
is considerable (excavation and installation of a septic
tank and inltration technology), but several house-
holds can share the costs if the system is designed for a
larger number of users. The maintenance costs may be
considerable, depending on the frequency and method
of tank emptying
2, 3.
Pour ush or cistern
ush toilet
Motorized emptying
and transport
Faecal sludge treatment
plant for sludge
and euent
Septic tank (or anaerobic
baed reactor or anaerobic
lter) connected to soak pit
or leach eld
Soil conditioner; solid fuel;
building materials;
irrigation; surface water
recharge
*
Toilet
Conveyance Treatment End use / disposalContainment
N/A N/A N/A
* Sludge: treated and used as soil conditioner, solid fuel or building materials. Euent: treated and used for irrigation or surface water recharge.
178
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
The capital cost of the treatment plant may also be
considerable, while the treatment plant maintenance
costs will depend on the technology chosen and the
energy required to operate it.
Design considerations
Toilet: The toilet should be made from concrete, bre-
glass, porcelain or stainless steel for ease of cleaning
and designed to prevent stormwater from inltrating
or entering the pit
2, 3
.
Containment (septic tank and soak pit): The septic tank
is sealed and impermeable but the soak pit is permeable
and designed to leach euent into the surrounding soil.
Therefore, the water table level and groundwater use
should be taken into consideration in order to avoid
contaminating drinking water. If groundwater is not
used for drinking or alternative cost-eective sources
can be used, then these options should be explored
before assuming that groundwater contamination by
the soak pit is a problem. Where groundwater is used for
drinking and to prevent its contamination, the bottom
of the soak pit should be at least 1.5m above the water
table
3
. In addition, the pit should be installed in areas
located down gradient of drinking water sources, and
at a minimum horizontal distance of 15m
4
.
This water-based system is suitable for cleansing water
inputs, and, since the solids are settled and digested
onsite, easily degradable dry cleansing materials
can also be used. However, rigid or non-degradable
materials (e.g., leaves, rags) could clog the system and
cause problems with emptying and, therefore, should
not be used. In cases when dry cleansing materials are
separately collected from the ush toilets, they should
be collected with solid waste and safely disposed of,
for example through burial or incineration. Greywater
can be managed along with blackwater in the same
containment technology; alternatively it can be man-
aged separately.
Conveyance: As the untreated sludge is full of patho-
gens, human contact and direct agricultural application
should be avoided. The emptied sludge should be
transported to a dedicated sludge treatment facility.
The conveyance technologies that can be used include
both manual or motorized emptying and transport. In
the event that a treatment facility is not easily accessible,
the sludge can be discharged to a transfer station. From
the transfer station it can then be transported to the
treatment facility by a motorized transport technology.
Treatment: The treatment technologies will produce
both euent and sludge, which may require further
treatment prior to end use and/or disposal. For example,
euent from a faecal sludge treatment facility could be
co-treated with wastewater in waste stabilization ponds
or in constructed wetlands.
End use/disposal: Options for the end use and/or
disposal of the treated euent include irrigation, sh
ponds, oating plant ponds or discharge to a surface
water body or to groundwater. Treated sludge can be
used in agriculture as a soil conditioner, as a solid fuel
or as an additive to construction materials
5
.
Operation and
maintenance considerations
Toilet and containment: The user is responsible for the
construction of the toilet and the septic tank, but they
are most likely to pay a mason to carry out the work.
The user will be responsible for cleaning and repairs to
the toilet, including the slab, seat/squatting plate and
superstructure, and for employing an emptying service
provider to empty the septic tank periodically
2
.
At shared facilities, a person (or persons) to clean and
carry out maintenance tasks on behalf of all users needs
to be identied as well as an emptying service provider.
Conveyance and treatment: The conveyance and
treatment part of the system is typically operated and
maintained by a combination of private and public
service providers working together; for example,
emptying and transport may be done by private and/
or public service providers who deliver faecal sludge to
treatment plants operated by public service providers.
All plant, tools and equipment used in the conveyance
and treatment steps will require regular maintenance
by the relevant service providers.
End use/disposal: Farmers and the general public will
be the main end users of the treatment products and
will be responsible for maintenance of all tools and
equipment they use
6
.
Mechanisms for protecting
public health
Toilet and containment (septic tank and soak pit): The
toilet separates users from excreta and the septic tank
isolates the blackwater and pathogens within it from
physical human contact.
During rains, the toilet and the impermeable septic
tank contain the fresh excreta and prevent it from
being washed away into surface water bodies, while
squat-hole covers or lids reduce disease transmission
by preventing disease carrying vectors from entering
and leaving the septic tank
2, 3
.
The septic tank is impermeable but the permeable
soak pit allows euent to leach into the surrounding
soil. Pathogens contained in the liquid are ltered out,
adsorbed onto particles, or die o during their slow
travel through soil
2, 3
.
179
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Conveyance: The conveyance step removes the patho-
gen hazard from the neighbourhood or local commu-
nity to a treatment plant. Motorized emptying using
vacuum trucks (or similar) tted with long-reach hoses
is the preferred method, as this reduces direct contact
by emptiers with the sludge. Nevertheless, emptying
and transport workers must wear personal protective
equipment and must follow standard operating proce-
dures. For instance, the wearing of boots, gloves, masks
and clothing that cover the whole body is essential, as
well as washing facilities and good hygiene practices.
The emptiers should not enter a septic tank but use long
handled shovels to remove any hard to shift sludge at
the bottom
6
.
Treatment: In order to reduce the risk of exposure of the
local community, all treatment plants must be securely
fenced to prevent people entering the site. To safeguard
workers’ health when operating the plant and carrying
out maintenance to tools and equipment, all treatment
plant workers must be trained in the correct use of all
tools and equipment they operate, wear appropriate
personal protective equipment and follow standard
operating procedures
6
.
End use/disposal: If correctly designed, constructed
and operated, treatment technologies can be combined
to reduce the pathogen hazard within the euent or
sludge by removal, reduction or inactivation to a level
appropriate for the intended end use and/or disposal
practice. For example, sludges require dewatering and
drying followed by co-composting with organics before
use as a compost-type soil conditioner, but for use as a
solid fuel or building material additive, they only require
dewatering and drying. Euent will require stabilization
and pathogen inactivation in a series of ponds or wet-
lands before use as crop irrigation water
5, 7, 8
.
To protect the health of themselves, co-workers and
the general public, end users must wear appropriate
protective equipment and follow standard operating
procedures in accordance with the actual level of treat-
ment and end use
6
.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Brikké F, and Bredero M (2003). Linking Technology
Choice with Operation and Maintenance in the Context
of Community Water Supply and Sanitation. A refer-
ence document for planners and project sta. Geneva,
Switzerland.
3. Reed R A, Scott R E, and Shaw R J. 2014. WEDC Guide
No. 25: Simple Pit Latrines. WEDC, Loughborough
University, UK.
4. Graham J, and Polizzotto M (2013). Pit latrines and
their impacts on groundwater quality: A systematic
review. Environmental Health Perspectives.
5. Strande L (2017). Introduction to Faecal Sludge
Management. Online Course available at: www.
sandec.ch/fsm_tools (accessed March 2017). Sandec:
Department of Sanitation, Water and Solid Waste
for Development Eawag: Swiss Federal Institute of
Aquatic Science and Technology.
6. World Health Organization (2015). Sanitation Safety
Planning – Manual for safe use and disposal of waste-
water, greywater and excreta. Geneva, Switzerland.
7. World Health Organization (2006). WHO Guidelines
for the safe use of wastewater, excreta and greywater.
Volumes I to IV. Geneva, Switzerland.
8. Stenström T A, Seidu R, Ekane N and Zurbrügg C
(2011). Microbial exposure and health assessments
in sanitation technologies and systems. Stockholm
Environment Institute (SEI).
180
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
Fact sheet 8
Urine-diverting dry toilet and container-based
sanitation with osite treatment of all contents
Summary
This system is designed to separate urine and faeces so
that they can be managed independently. Inputs to the
system can include faeces, urine, cleansing water and
dry cleansing materials.
The main toilet technology for this system is a urine-di-
verting dry toilet (UDDT), which allows urine and faeces
to be separately managed. A urinal could additionally
be used. UDDT designs vary and include adaptations for
dierent preferences, for instance with a third diversion
for cleansing water management.
The UDDT conguration ensures that the faeces, cleans-
ing water and/or dry cleansing materials, which when
combined comprise a relatively thick brownwater, pass
into a portable container. This is commonly referred to
as a cartridge that is portable. Once a brownwater car-
tridge is full, it is removed/collected and transported to
treatment using either motorized or manual transport.
After dewatering and drying, the faeces can be used as
a solid fuel or, more commonly, they are co-composted
with organics and used as a soil conditioner.
Depending on the demand for urine end use and local
requirements, the UDDT diverts the urine to the ground
for inltration through a soak pit. Alternatively, it can
be directed into a portable container where it is stored.
Stored urine can be collected and transported for use
on neighbouring elds
2
using manual or motorized
transport technologies, as indicated in the schematic.
Applicability
Suitability: This is a relatively new system typically
implemented in dense, informal, urban locations and in
emergency contexts, in particular, where there is limited
space and/or soil conditions are not appropriate for the
construction of underground pits and tanks; where
there is a risk of surface ooding; where the water table
is high; where there is no sewer network for users to
connect to; or where tenants cannot aord the higher
capital cost of other containment technologies.
Cost: The users often pay no capital or initial cost. In-
stead, they pay a weekly or monthly fee to the service
provider for removal of full brownwater cartridges and
urine cartridges (if any) and replacing them with clean,
empty cartridges.
Urine-diverting dry toilet
Brownwater: Collection
and motorized (or manual)
transport of storage tanks
Brownwater treatment plant
– for euent and sludge
Brownwater: Portable
storage container or
cartridge
Soil conditioner; solid fuel;
building materials;
irrigation; surface water
recharge
*
Toilet
Conveyance Treatment End use / disposalContainment
Urine: Collection and
motorized (or manual)
transport of storage tanks
N/A
Urine: Portable storage
tanks or jerry cans
Urine: used as
liquid fertilizer
* Sludge: treated and used as soil conditioner, solid fuel or building materials. Euent: treated and used for irrigation or surface water recharge.
181
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Urine-diverting dry toilet and container-based
sanitation with osite treatment of all contents
The treatment plant capital cost and operation and
maintenance cost will depend on the technology chosen
and the energy required to operate it. These costs can
be signicantly reduced where brownwater treatment
can be combined into an existing plant; however, where
a new dedicated plant is required then the costs could
be considerable.
Overall, this system is most appropriate when there is
a high willingness and ability to pay for the contain-
er-based service, where there is an appropriate facility
for the brownwater treatment and a demand for the
end use products.
Design considerations
Toilet and containment (cartridges): Container-based
urine-diverting toilets are generally prefabricated,
modular units that connect directly to the cartridges
into which they discharge. They are often made from
breglass or rigid plastics, which are relatively light in
weight, portable, durable and easy to clean.
A separate system is required for stormwater and
greywater, neither of which should enter into the car-
tridges. The toilets should be designed to prevent rain
or stormwater from entering the cartridges.
This system is suitable for cleansing water inputs, and
easily degradable dry cleansing materials can be used.
However, rigid or non-degradable materials (e.g., leaves,
rags) could block the system and should not be used.
In cases when dry cleansing materials are separately
collected from the toilets, they should be collected with
solid waste and safely disposed of, for example through
burial or incineration.
Conveyance: As the untreated brownwater is full of
pathogens, human contact and direct agricultural appli-
cation should be avoided. The (ideally) sealed containers
should be transported to a dedicated treatment facility
using either manual or motorized transport.
Treatment: Treatment of brownwater will produce
both euent and sludge, which may require further
treatment prior to end use and/or disposal. For example,
euent produced from dewatering could be co-treat-
ed with wastewater in waste stabilization ponds or in
constructed wetlands.
End use/disposal: Treated brownwater can either be
used in agriculture as a soil conditioner or used as a solid
fuel or as an additive to construction materials.
Operation and
maintenance considerations
Toilet and containment (cartridge): The toilet, contain-
ment and conveyance steps are commonly operated by
a private company (service provider) who is responsible
for providing the user with a toilet, cartridge(s) and
instructions on their operation and maintenance.
The user is responsible for cleaning the toilet and main-
taining the toilet cubicle. At shared toilet facilities, a
person (or persons) to clean the toilets and carry out
other maintenance tasks (e.g. repairs to superstructure)
on behalf of all users needs to be identied.
Conveyance: The provider’s service will also include
regular (either demand–based or xed interval-based)
replacement of a full brownwater cartridge with a clean,
empty cartridge and the removal and transport of the
full cartridge to treatment. Where urine is stored in a
cartridge, the service may also include removal and
transport of a full urine cartridge and replacement with
an empty one. The service provider will be responsible
for cleaning of all cartridges and maintenance of all
transport equipment.
Treatment: Functioning, properly maintained treatment
technologies are a key requirement. In most situations
these are managed at the municipal or regional level.
In the case of more local, small-scale systems, operation
and maintenance of the collection and transport service
and the treatment plant, is managed and organized by
private service providers at the community level. All
machinery, tools and equipment used in the treatment
step will require regular maintenance by the relevant
service provider.
End use/disposal: Farmers and the general public will
be the main end users of the treatment products and
will be responsible for maintenance of all tools and
equipment they use
2
.
Mechanisms for protecting
public health
Toilet: The toilet separates the excreta from direct hu-
man contact, and squat-hole covers or lids can reduce
disease transmission by preventing disease carrying
vectors from entering and leaving the cartridges.
Containment (cartridges): The urine requires storage
before use in sealed cartridges or direct discharge to the
ground; both methods will protect public health when
operated correctly
2
.
The watertight cartridges isolate the brownwater from
physical human contact and ensure surface waters and
groundwater are not contaminated. The conveyance
step then removes the pathogen containing brown-
water from the neighbourhood or local community to
a treatment plant.
Conveyance: To reduce the risk of exposure from
spillages when moving and transporting full cartridges
to treatment, all workers require personal protective
equipment and must follow standard operating proce-
182
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
dures. For instance, the wearing of boots, gloves, masks
and clothing that cover the whole body is essential, as
well as washing facilities and good hygiene practices
2
.
Treatment: In order to reduce the risk of exposure
of the local community, all treatment plants must be
securely fenced to prevent people entering the site, and
to safeguard workers’ health when operating the plant
and carrying out maintenance to tools and equipment,
all treatment plant workers must be trained in the cor-
rect use of all tools and equipment they operate, wear
appropriate personal protective equipment and follow
standard operating procedures
2
.
End use/disposal: If correctly designed, constructed
and operated, treatment technologies can be combined
to reduce the pathogen hazard within the brownwa-
ter by removal, reduction or inactivation to a level
appropriate for the intended end use and/or disposal
practice. For example, the thick brownwater will require
dewatering and drying followed by co-composting with
organics before use as a compost-type soil conditioner,
but for use as a solid fuel or building material additive,
it will only require dewatering and drying
3, 4
.
To protect the health of themselves, co-workers and
the general public, end users must wear appropriate
protective equipment and follow standard operating
procedures in accordance with the actual level of treat-
ment and end use
2
.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. World Health Organization (2015). Sanitation Safety
Planning – Manual for safe use and disposal of waste-
water, greywater and excreta. Geneva, Switzerland.
3. Strande L (2017). Introduction to Faecal Sludge
Management. Online Course available at: www.
sandec.ch/fsm_tools (accessed March 2017). Sandec:
Department of Sanitation, Water and Solid Waste
for Development Eawag: Swiss Federal Institute of
Aquatic Science and Technology.
4. World Health Organization (2006). WHO Guidelines
for the safe use of wastewater, excreta and greywater.
Volumes I to IV. Geneva, Switzerland.
183
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Fact sheet 9
Flush toilet with septic tank, sewerage and
osite treatment of faecal sludge and euent
Summary
This system is characterized by the use of a house-
hold-level containment technology to remove and
digest settleable solids from the blackwater, and a sewer
system to transport the euent to a treatment facility.
Inputs to the system can include faeces, urine, ushwater,
cleansing water, dry cleansing materials and greywater.
There are two toilet technologies that can be used for
this system: a pour ush toilet or a cistern ush toilet.
A urinal could additionally be used. This system is com-
parable to Fact sheet 7 (Flush toilet with septic tank,
sewerage and osite treatment of faecal sludge and
euent) except that the management of the euent
generated during containment of the blackwater is dif-
ferent: the euent from septic tanks, anaerobic baed
reactors or anaerobic lters is transported to a treatment
facility via a solids-free sewer.
The containment technologies serve as “interceptor
tanks” and allow for the use of small-diameter sewers,
as the euent is free from settleable solids.
The sewer system transports euent to a treatment
facility where it is treated and will produce both sludge
and euent, which may require further treatment prior
to end use or disposal.
Applicability
Suitability: This system is especially appropriate for
urban settlements where the soil is not suitable for
the inltration of euent. Since the sewer network is
shallow and (ideally) watertight, it is also applicable for
areas with high groundwater tables. This system can be
used as a way of upgrading existing, under-performing
containment technologies (e.g., septic tanks) by provid-
ing improved treatment.
There must be a constant supply of water to ensure that
the sewers do not become blocked.
Cost: For the user, the capital investment for this system
is considerable (excavation and installation of an inter-
ceptor tank), but several households can share the costs
if the system is designed for a larger number of users.
The maintenance costs may be considerable, depend-
ing on the frequency and method of tank emptying.
Pour ush or cistern
ush toilet
Motorized emptying
and transport
Faecal sludge
treatment plant
Interceptor tank (e.g.
septic tank, anaerobic
baed reactor or anaerobic
lter) connected to a
solids free sewer
Sludge: treated and used
as soil conditioner, solid
fuel or building materials
Toilet
Conveyance Treatment End use / disposalContainment
Solids-free sewer
for euent
Euent treatment plant
Euent: treated and used
for irrigation or surface
water recharge
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Annex 1
With the sewer-based transport of euent to a treatment
facility, the capital investment is considerable. However,
the design and installation of solids-free sewers will be
considerably less expensive than a conventional gravity
sewer network.
The capital cost of the treatment plant may also be
considerable, while the treatment plant maintenance
costs will depend on the technology chosen and the
energy required to operate it.
Overall, this system is most appropriate when there
is a high willingness and ability to pay for the capital
investment and maintenance costs and where there is
an appropriate treatment facility.
Design considerations
Toilet: The toilet should be made from concrete, bre-
glass, porcelain or stainless steel for ease of cleaning
and designed to prevent stormwater from inltrating
or entering the tank.
Containment: This water-based system is suitable for
cleansing water inputs, and, since the solids are settled
and digested onsite, easily degradable dry cleansing
materials can be used. However, rigid or non-degradable
materials (e.g., leaves, rags) could clog the system and
cause problems with emptying and should not be used.
In cases when dry cleansing materials are separately
collected from the ush toilets, they should be collected
with solid waste and safely disposed of, for example
through burial or incineration.
End use/disposal: Options for the end use and/or
disposal of the treated euent include irrigation, sh
ponds, oating plant ponds or discharge to a surface
water body or to groundwater
2
.
Treated sludge can be used in agriculture as soil con-
ditioner, as a solid fuel, or as an additive to construc-
tion materials.
Operation and
maintenance considerations
Toilet and containment: The user is responsible for the
construction of the toilet and interceptor tank, but they
are most likely to pay a mason to carry out the work. The
user will be responsible for cleaning of the toilet and will
most likely pay an emptying service provider to empty
the interceptor tank periodically.
At shared facilities, a person (or persons) to clean and
carry out other maintenance tasks (e.g. repairs to super-
structure) on behalf of all users needs to be identied
as well as an emptying service provider.
Conveyance, treatment and end use/disposal: The
success of this system depends on the conveyance
systems. There must be an aordable and systematic
method for emptying sludge from the interceptor tanks
since one user’s improperly maintained tank could
adversely impact the entire sewer network.
Typically, the technologies may be operated and main-
tained by a combination of private and public service
providers working together; for example, emptying and
transport may be done by private and/or public service
providers who maintain the sewer network and also
deliver faecal sludge to treatment plants operated by
public service providers.
Functioning, properly maintained sludge and euent
treatment technologies are a key requirement. In most
situations these are managed at the municipal or region-
al level. In the case of more local, small-scale systems,
operation and maintenance of the emptying and trans-
port service, the sewer network and the treatment plant,
are managed and organized at the community level
3
.
Importantly, for this system, all machinery, tools and
equipment used in the conveyance, treatment and end
use/disposal steps will require regular maintenance by
the service providers.
Mechanisms for protecting
public health
Toilet: The toilet separates users from excreta and the
impermeable interceptor tank isolates the blackwater
and pathogens within it from physical human contact.
During rains, the slab and the impermeable interceptor
tank contain the fresh excreta and prevent it from being
washed away into surface water bodies, while the water
seal reduces smells, nuisance and disease transmission
by preventing disease carrying vectors from entering
and leaving the tank.
Conveyance: The conveyance step removes the
pathogen hazard from the neighbourhood or local
community to a treatment plant. The watertight sewer
network isolates the blackwater from physical human
contact and ensures groundwater is not contaminated.
Motorized emptying using vacuum trucks (or similar)
tted with long-reach hoses is the preferred method
of removing the sludge, as this reduces direct contact
by emptiers. Nevertheless, emptying and transport
workers must wear personal protective equipment and
follow standard operating procedures. For instance, the
wearing of boots, gloves, masks and clothing that cover
the whole body is essential, as well as washing facilities
and good hygiene practices. The emptiers should not
enter an interceptor tank but use long handled shovels
to remove any hard to shift sludge at the bottom
4
.
185
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Treatment and end use/disposal: If correctly designed,
constructed and operated, treatment technologies can
be combined to reduce the pathogen hazard within
the euent or sludge by removal, reduction or inacti-
vation to a level appropriate for the intended end use
and/or disposal practice. For example, sludges require
dewatering and drying followed by co-composting with
organics before use as a compost-type soil conditioner,
but for use as a solid fuel or building material additive,
they only require dewatering and drying. Euent will
require stabilization and pathogen inactivation in a
series of ponds or wetlands before use as crop irrigation
water
2, 5, 6
.
In order to reduce the risk of exposure of the local com-
munity, all treatment plants must be securely fenced
to prevent people entering the site; and to safeguard
workers’ health when operating the plant and carrying
out maintenance to tools and equipment, all treatment
plant workers must wear appropriate protective equip-
ment and follow standard operating procedures
4
.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Strande L (2017). Introduction to Faecal Sludge
Management. Online Course available at: www.
sandec.ch/fsm_tools (accessed March 2017). Sandec:
Department of Sanitation, Water and Solid Waste
for Development Eawag: Swiss Federal Institute of
Aquatic Science and Technology.
3. Brikké F, and Bredero M (2003). Linking Technology
Choice with Operation and Maintenance in the Context
of Community Water Supply and Sanitation. A refer-
ence document for planners and project sta. Geneva,
Switzerland.
4. World Health Organization (2015). Sanitation Safety
Planning – Manual for safe use and disposal of waste-
water, greywater and excreta. Geneva, Switzerland.
5. World Health Organization (2006). WHO Guidelines
for the safe use of wastewater, excreta and greywater.
Volumes I to IV. Geneva, Switzerland.
6. Stenström T A, Seidu R, Ekane N and Zurbrügg C
(2011). Microbial exposure and health assessments
in sanitation technologies and systems. Stockholm
Environment Institute (SEI).
186
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
Pour ush or cistern
ush toilet
Soil conditioner; solid fuel; building
materials; irrigation;
surface water recharge *
Fact sheet 10
Flush toilet with sewerage and osite
wastewater treatment
Summary
This is a water-based sewer system in which wastewater
is transported to a treatment facility. Importantly, unlike
the system described in Fact sheet 9, in this system there
is no interceptor tank (i.e. a containment technology
such as a septic tank).
Inputs to the system include faeces, urine, ushwater,
cleansing water, dry cleansing materials, greywater and
possibly stormwater.
There are two toilet technologies that can be used for
this system: a pour ush toilet or a cistern ush toilet.
A urinal could additionally be used. The blackwater
that is generated at the toilet together with greywater
is directly conveyed to a treatment facility through a
conventional or a simplied gravity sewer network.
As there is no containment, all of the blackwater is trans-
ported to a treatment facility where a combination of
technologies is used to produce treated euent for end
use and/or disposal, and wastewater sludge. This sludge
must be further treated prior to end use and/or disposal.
Applicability
Suitability: This system is especially appropriate for
dense, urban and peri-urban settlements where there
is little or no space for onsite containment technologies
or emptying. The system is not well-suited to rural areas
with low housing densities.
Since the sewer network is (ideally) watertight, it is also
applicable for areas with high groundwater tables.
The system requires a constant supply of water for ush-
ing, to ensure that the sewers do not become blocked.
Cost: The capital investment for this system can be very
high. Conventional gravity sewers require extensive
excavation and installation that is expensive, whereas
simplied sewers use smaller diameter pipes laid at a
shallower depth and at a atter gradient, so are gener-
ally less expensive.
Users may be required to pay a connection fee and
regular user fees for system maintenance; the size of
the fees will depend on the operation and maintenance
arrangement and whether or not the local topography
dictates that the blackwater requires pumping to reach
the treatment plant.
The capital cost of the treatment plant may also be
considerable, while the treatment plant maintenance
costs will depend on the technology chosen and the
energy required to operate it.
Overall, this system is most appropriate when there
is a high willingness and ability to pay for the capital
investment and maintenance costs and where there is
an appropriate treatment facility.
Design considerations
Toilet: The toilet should be made from concrete, bre-
glass, porcelain or stainless steel for ease of cleaning
and designed to prevent stormwater from inltrating
or entering the sewer.
Simplied or conventional
gravity sewer
Toilet Conveyance
End use / disposalTreatment
Wastewater treatment plant – for
wastewater and wastewater sludge
* Sludge: treated and used as soil conditioner, solid fuel or building materials. Euent: treated and used for irrigation or surface water recharge.
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ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Conveyance: This water-based system is suitable for
cleansing water inputs, and easily degradable dry
cleansing materials can be used. However, rigid or
non-degradable materials (e.g., leaves, rags) could block
the system and should not be used. In cases when dry
cleansing materials are separately collected from the
ush toilets, they should be collected with solid waste
and safely disposed of, for example through burial
or incineration.
The inclusion of greywater in the conveyance tech-
nology helps to prevent solids from accumulating in
the sewers and stormwater could also be put into the
gravity sewer network. However, this would dilute the
wastewater and require stormwater overows. Local
retention and inltration of stormwater, or a separate
drainage system for rain and stormwater are therefore
preferred approaches.
Treatment: Typically, the wastewater treatment technol-
ogy will consist of a series of ponds or wetlands, which
can produce a stabilized, pathogen-free euent, which
is suitable for use as crop irrigation water. As well as
euent, the treatment technology will produce waste-
water sludge, which may require further treatment prior
to end use and/or disposal. For example, dewatered and
dried wastewater sludge can be used as a solid fuel or
as an additive to construction materials.
End use/disposal: Options for the end use and/or
disposal of the treated euent include irrigation, sh
ponds, oating plant ponds or discharge to a surface
water body or to groundwater
2
.
Operation and
maintenance considerations
Toilet: The user is responsible for the construction,
maintenance and cleaning of the toilet.
At shared toilet facilities, a person (or persons) to clean
and carry out other maintenance tasks (e.g. repairs
to superstructure) on behalf of all users needs to be
identied as well as an emptying service provider.
Conveyance: Depending on the sewer type and
management structure (simplied vs. conventional,
city-managed vs. community-operated) there will be
varying degrees of operation or maintenance responsi-
bilities for the user. Where conventional, city-managed
sewerage is found, users’ involvement will be limited to
paying user fees and reporting problems to the service
provider. In contrast, if simplied, community-operated
sewerage is used, users may help the community organ-
ization inspect, repair and/or unblock the sewer line
3.
Treatment: Functioning, properly maintained waste-
water and sludge treatment technologies are a key
requirement. In most situations these are managed at
the municipal or regional level. In the case of small-scale
systems, operation and maintenance of the treatment
plant is managed and organized at the community
level. All machinery, tools and equipment used in the
treatment step will require regular maintenance by the
relevant service providers.
End use/disposal: Farmers and the general public will
be the main end users of the treatment products and
will be responsible for maintenance of all tools and
equipment they use
4
.
Mechanisms for protecting
public health
Toilet: The toilet separates the excreta from direct
human contact, and the water seal reduces smells, nui-
sance and disease transmission by preventing disease
carrying vectors from entering and leaving the sewer.
Conveyance: The conveyance step removes the path-
ogen-containing blackwater from the neighbourhood
or local community to a treatment plant. The (ideally)
watertight sewer network isolates the blackwater from
physical human contact and ensures groundwater is
not contaminated.
As the blackwater contains pathogens, when clearing
blockages or repairing sewers, all workers require per-
sonal protective equipment and must follow standard
operating procedures. For instance, the wearing of
boots, gloves, masks and clothing that cover the whole
body is essential, as well as washing facilities and good
hygiene practices
4
.
Treatment: In order to reduce the risk of exposure
of the local community, all treatment plants must be
securely fenced to prevent people entering the site, and
to safeguard workers’ health when operating the plant
and carrying out maintenance to tools and equipment,
all treatment plant workers must be trained in the cor-
rect use of all tools and equipment they operate, wear
appropriate personal protective equipment and follow
standard operating procedures
4
.
End use/disposal: If correctly designed, constructed
and operated, treatment technologies can be combined
to reduce the pathogen hazard within the euent or
sludge by removal, reduction or inactivation to a level
appropriate for the intended end use and/or disposal
practice. For example, euent requires stabilization and
pathogen inactivation in a series of ponds or wetlands
before use as crop irrigation water. While sludges require
dewatering and drying followed by co-composting with
organics before use as a compost-type soil conditioner,
but for use as a solid fuel or building material additive,
they only require dewatering and drying
2, 5, 6
.
188
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
To protect the health of themselves, co-workers and
the general public, end users must wear appropriate
protective equipment and follow standard operating
procedures in accordance with the actual level of treat-
ment and end use
4
.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Strande L (2017). Introduction to Faecal Sludge
Management. Online Course available at: www.
sandec.ch/fsm_tools (accessed March 2017). Sandec:
Department of Sanitation, Water and Solid Waste
for Development Eawag: Swiss Federal Institute of
Aquatic Science and Technology.
3. Brikké F, and Bredero M (2003). Linking Technology
Choice with Operation and Maintenance in the Context
of Community Water Supply and Sanitation. A refer-
ence document for planners and project sta. Geneva,
Switzerland.
4. World Health Organization (2015). Sanitation Safety
Planning – Manual for safe use and disposal of waste-
water, greywater and excreta. Geneva, Switzerland.
5. World Health Organization (2006). WHO Guidelines
for the safe use of wastewater, excreta and greywater.
Volumes I to IV. Geneva, Switzerland. 2006.
6. Stenström T A, Seidu R, Ekane N and Zurbrügg C
(2011). Microbial exposure and health assessments
in sanitation technologies and systems. Stockholm
Environment Institute (SEI).
189
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
Fact sheet 11
Urine-diverting ush toilet with sewerage and
osite wastewater treatment
Summary
This is a water-based system that requires a urine-divert-
ing ush toilet (UDFT) and a sewer. The UDFT is a special
toilet that allows for the separate collection of urine
without water, although it uses water to ush faeces.
Inputs to the system can include faeces, urine, ushwa-
ter, cleansing water, dry cleansing materials, greywater
and possibly stormwater.
The main toilet technology for this system is the UDFT.
A urinal could additionally be used. Brownwater and
urine are separated at the toilet. Brownwater bypasses
the urine storage tank and is conveyed to a treatment
facility using a simplied or a conventional gravity sewer
network.
Brownwater is treated at a treatment facility where a
combination of technologies is used to produce treated
euent for end use and/or disposal, and wastewater
sludge. This sludge must be further treated prior to end
use and/or disposal.
Urine diverted at the toilet is collected in a storage tank.
Stored urine can be handled easily and with little risk
because it is nearly sterile. With its high nutrient content
it can be used as a good liquid fertilizer. Stored urine can
be transported using manual or motorized transport
technologies. Alternatively, the urine can be diverted
directly to the ground for inltration through a soak pit.
Applicability
Suitability: This system is only appropriate when there
is an end use and therefore a need for the separated
urine, and/or when there is a desire to limit water
consumption by using a low-ush UDFT (although the
system still requires a constant source of water).
Depending on the type of sewers used, this system can
be adapted for both dense urban and peri-urban areas.
It is not well-suited to rural areas with low housing den-
sities. Since the sewer network is (ideally) watertight, it is
also applicable for areas with high groundwater tables.
Cost: UDFTs are not common and the capital cost for
this system can be very high. This is partly due to the fact
that there is limited competition in the toilet market and
Urine-diverting ush toilet
Urine: Manual or
motorized transport
NoneUrine: Jerry cans or tanks Urine: used for irrigation
Toilet
Conveyance Treatment End use / disposalContainment
Brownwater: simplied or
conventional gravity sewer
Treatment plant for
brownwater and
wastewater sludge
Soil conditioner; solid
fuel; building materials;
irrigation; surface water
recharge*
* Soil conditioner; solid fuel; building materials; irrigation; surface water recharge*
N/A
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WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
also because high quality workmanship is required for
the dual plumbing system. Conventional gravity sewers
require extensive excavation and installation, which is
expensive, whereas simplied sewers are generally less
expensive if the site conditions permit a condominial
design.
Users may be required to pay a connection fee and reg-
ular user fees for system maintenance; this will depend
on the operation and maintenance arrangement.
The capital cost of the treatment plant may also be
considerable, while the treatment plant maintenance
costs will depend on the technology chosen and the
energy required to operate it.
Overall, this system is most appropriate when there
is a high willingness and ability to pay for the capital
investment and maintenance costs and where there is
an appropriate treatment facility.
Design considerations
Toilet: The toilet should be made from concrete, bre-
glass, porcelain or stainless steel for ease of cleaning
and designed to prevent stormwater from inltrating
or entering the sewer.
This water-based system is suitable for cleansing water
inputs, and easily degradable dry cleansing materials
can be used. However, rigid or non-degradable mate-
rials (e.g., leaves, rags) could clog the system and cause
problems and should not be used. In cases when dry
cleansing materials are separately collected from the
ush toilets, they should be collected with solid waste
and safely disposed of, for example through burial
or incineration.
Conveyance: The gravity sewer network can transport
greywater to treatment, where the combined ows are
treated together. Stormwater could also be put into the
gravity sewer network, although this would dilute the
wastewater and require stormwater overows. Local
retention and inltration of stormwater, or a separate
drainage system for rain and stormwater are therefore
preferred approaches.
End use/disposal: Options for the end use and/or
disposal of the treated euent include irrigation, sh
ponds, oating plant ponds or discharge to a surface
water body or to groundwater
2
.
Treated sludge can be used in agriculture as soil condi-
tioner, as a solid fuel, or as an additive to construction
materials
3
.
Operation and
maintenance considerations
Toilet: The user is responsible for the construction,
maintenance and cleaning of the UDFT.
At shared toilet facilities, a person (or persons) to clean
and carry out other maintenance tasks (e.g. repairs
to superstructure) on behalf of all users needs to be
identied, as well as a urine transport service provider.
Conveyance: Depending on the sewer type and
management structure (simplied vs. conventional,
city-managed vs. community-operated) there will be
varying degrees of operation or maintenance respon-
sibilities for the user
4
.
Treatment and end use/disposal: Functioning, prop-
erly maintained wastewater and sludge treatment
technologies are a key requirement. In most situations
these are managed at the municipal or regional level.
In the case of more local, small-scale systems, operation
and maintenance of the urine transport service, the
sewer network and the treatment plant are managed
and organized at the community level
4
.
Importantly, for this system, all plants, tools and equip-
ment used in the containment, conveyance, treatment
and end use/disposal steps will require regular mainte-
nance by the service providers.
Mechanisms for protecting
public health
Toilet and containment: The toilet separates the ex-
creta from direct human contact, and the water seal
reduces smells, nuisance and disease transmission by
preventing disease carrying vectors from entering and
leaving the sewer.
The urine poses little health risk as it is nearly sterile,
and storage before use in sealed containers will pro-
tect public health
3
. In areas in which schistosomiasis
is endemic, urine should not be used in water-based
agriculture, such as rice paddies
Conveyance: The conveyance step removes the path-
ogen-laden brownwater from the neighbourhood or
local community to a treatment plant. The (ideally)
watertight sewer network isolates the brownwater from
physical human contact and ensures groundwater is
not contaminated.
When clearing blockages or repairing sewers, all workers
require personal protective equipment as well as stand-
ard operating procedures. For instance, the wearing of
boots, gloves, masks and clothing that cover the whole
body is essential, as well as washing facilities and good
hygiene practices
5
.
Treatment and end use/disposal: If correctly designed,
constructed and operated, treatment technologies can
be combined to reduce the pathogen hazard within the
euent or sludge by removal, reduction or inactivation
to a level appropriate for the intended end use and/or
disposal practice. For example, euent requires stabi-
191
ANNEX 1. SANITATION SYSTEM FACT SHEETS
Annex 1
lization and pathogen inactivation in a series of ponds
or wetlands before use as crop irrigation water. Sludges
require dewatering and drying followed by co-com-
posting with organics before use as a compost-type
soil conditioner, but for use as a solid fuel or building
material additive, they only require dewatering and
drying
2, 3, 6
.
In order to reduce the risk of exposure of the local com-
munity, all treatment plants must be securely fenced
to prevent people entering the site, and to safeguard
workers’ health when operating the plant and carrying
out maintenance to tools and equipment, all treatment
plant workers must wear appropriate protective equip-
ment and follow standard operating procedures.
References
The text for this fact sheet is based on Tilley, et al.
1
unless
otherwise stated.
1. Tilley E, Ulrich L, Lüthi C, Reymond P, Schertenleib
R, and Zurbrügg C (2014). Compendium of Sanitation
Systems and Technologies. 2nd Revised Edition. Swiss
Federal Institute of Aquatic Science and Technology
(Eawag).
2. Strande L (2017). Introduction to Faecal Sludge
Management. Online Course available at: www.
sandec.ch/fsm_tools (accessed March 2017). Sandec:
Department of Sanitation, Water and Solid Waste
for Development Eawag: Swiss Federal Institute of
Aquatic Science and Technology.
3. Stenström T A, Seidu R, Ekane N and Zurbrügg C
(2011). Microbial exposure and health assessments
in sanitation technologies and systems. Stockholm
Environment Institute (SEI).
4. Brikké F, and Bredero M (2003). Linking Technology
Choice with Operation and Maintenance in the Context
of Community Water Supply and Sanitation. A refer-
ence document for planners and project sta. Geneva,
Switzerland.
5. World Health Organization (2015). Sanitation Safety
Planning – Manual for safe use and disposal of waste-
water, greywater and excreta. Geneva, Switzerland.
6. World Health Organization (2006). WHO Guidelines
for the safe use of wastewater, excreta and greywater.
Volumes I to IV. Geneva, Switzerland. 2006.
192
WHO GUIDELINES ON SANITATION AND HEALTH
Annex 1
193
ANNEX 2. GLOS SARY
Annex 2
Biochemical oxygen demand (BOD)
A measure of the oxygen used by microorganisms
to degrade organic matter. The oxygen demand is
reduced through stabilisation, and can be achieved
by aerobic or anaerobic treatment.
Biogas
Biogas is the common name for the mixture of
gases released from anaerobic digestion. Biogas is
comprised of methane (50 to 75%), carbon dioxide (25
to 50%) and varying quantities of nitrogen, hydrogen
sulphide, water vapour and other components. Biogas
can be collected and burned for fuel (like propane).
Biomass
Biomass refers to plants or animals cultivated
using the water and/or nutrients owing through a
sanitation system. Biomass may include sh, insects,
vegetables, fruit, forage or other benecial crops
that can be utilized for food, feed, fibre and fuel
production.
Blackwater
Blackwater is the mixture of urine, faeces and
ushwater along with anal cleansing water (if water
is used for cleansing) and/or dry cleansing materials.
Blackwater contains the pathogens of faeces and
urine and the nutrients of urine that are diluted in
the ushwater.
Brownwater
Brownwater is the mixture of faeces and ushwater,
and does not contain urine. Urine-diverting ush
toilets generate it and, therefore, the volume depends
on the volume of the ushwater used. The pathogen
and nutrient load of faeces is not reduced, only diluted
by the ushwater. Brownwater may also include anal
cleansing water (if water is used for cleansing) and/
or dry cleansing materials.
By-law
A regulation made by a local authority or corporation;
a rule made by a company or society to control the
actions of its members.
Centralised sewer system
A system used to collect, treat, discharge, and/or
reclaim wastewater from large user groups (i.e.
neighbourhood to city level applications).
Cleansing water
Water used for cleansing after defecating and/
or urinating; those who use water, rather than dry
material, for cleansing, generate it. The volume of water
used per cleaning typically ranges from 0.5– to 3 l.
Combined sewer
Sewer network where blackwater and/or stormwater
runo are carried by the same sewers.
Compost
Compost is decomposed organic matter that results
from a controlled aerobic degradation process.
Containment
Containment describes the ways of collecting, storing,
and sometimes treating the products generated at
the toilet (or user interface). The treatment provided
Annex 2
GLOSSARY
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by these technologies is often a function of storage
and is usually passive (e.g., requiring no energy input).
Thus, products that are ‘treated’ by these technologies
often require subsequent treatment before use and/
or disposal.
Container-based sanitation
A sanitation service in which excreta is captured
in sealable containers that are then transported to
treatment facilities.
Control measure
Any action and activity (or barrier) that can be used
to prevent or eliminate a sanitation-related hazard,
or reduce it to an acceptable level.
Conveyance
Conveyance describes the transport of products
from either the toilet or containment step to the
treatment step of the sanitation service chain. For
example, where sewer-based technologies transport
wastewater from toilets to wastewater treatment
plants.
Disability-adjusted Life Year (DALY)
Population metric of life years lost to disease due to
both morbidity and mortality.
Downstream consumers
In this document refers to the wider general public
(e.g., farmers) who use sanitation products (e.g.,
compost or water) or consume products (e.g., sh or
crops) that are produced using sanitation products,
and may be either actively or passively aected.
Dry cleansing material
Dry cleansing materials are solid materials used for
cleansing after defecating and/or urinating (e.g.,
paper, leaves, corncobs, rags or stones).
Euent
Euent is the general term for a liquid that leaves a
technology, typically after blackwater or faecal sludge
has undergone solids separation or some other type
of treatment.
End use/disposal
In this document refers to the methods by which
products are ultimately returned to the environment
as reduced-risk materials and/or used in resource
recovery. If there is an end use for the output they
can be applied or used, otherwise they should be
disposed of in ways that are least harmful to the
public and the environment.
Excreta
Urine and faeces.
Exposure
Contact of a chemical, physical or biological agent
with the outer boundary of an organism (e.g. through
inhalation, ingestion or dermal [skin] contact).
Exposure route or pathway
The pathway or route by which a person is exposed
to a hazard.
Faecal sludge
Solid and liquid wastes removed from on-site storage
containers, also called septage when removed from
septic tanks
Faeces
(Semisolid) excrement that is not mixed with urine
or water.
Flushwater
Flushwater is the water discharged into the user
interface to transport the content and/or clean it.
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Greywater
Greywater is the total volume of water generated
from the household, but not from toilets.
Hazard
A biological, chemical or physical constituent that can
cause harm to human health.
ID50
Dose at which 50% of subjects would become
infected; or probability of infection = 0.5.
Hazardous event
Any incident or situation that
• Introduces or releases the hazard to the
environment in which humans are living or
working, or
• Amplifies the concentration of a hazard in the
environment in which people are living or working,
or
• Fails to remove a hazard from the human
environment.
Leachate
The liquid fraction that is separated from the solid
component by gravity ltration through media (e.g.,
liquid that drains from drying beds).
Legislation
Laws, considered collectively, as well as the process
of making or enacting laws.
Local community
In this document refers to the people who live and/
or work near to, or downstream from, the sanitation
system, and may be either actively or passively
aected.
Log reduction
Organism reduction eciencies: 1 log unit = 90%; 2
log units = 99%; 3 log units = 99.9%; and so on.
Low-income country
Low-income economies are dened as those with a
GNI per capita, calculated using the World Bank Atlas
method, of $995 or less in 2017.
Manual emptying
In this document refers to the emptying of faecal
sludge from on-site sanitation technologies, where
humans are required to manually lift the sludge.
Manual emptying can be used with either manual or
motorized transport.
Manual transport
In this document refers to the human-powered
transport of faecal sludge emptied from on-site
sanitation technologies. Manual transport can be
used with manual or motorized emptying.
Mechanical vector transmission
The mechanical transfer of pathogens in excreta,
faecal sludge or wastewater by insect (e.g. ies) or
vermin (e.g. rats) to a person or food items.
Middle-income country
Lower middle-income economies are those with
a GNI per capita between $996 and $3,895; upper
middle-income economies are those with a GNI per
capita between $3,896 and $12,055, calculated using
the World Bank Atlas.
Motorized emptying
In this document refers to the use of motorized
equipment for the emptying of faecal sludge from
on-site sanitation technologies. Humans are required
to operate the equipment and manoeuvre the hose,
but the faecal sludge is not manually lifted. Motorized
emptying is most commonly followed by motorized
transport, but it is also used with manual transport.
Motorized transport
In this document refers to the use of motorized
equipment for the transport of faecal sludge from
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on-site sanitation technologies. Humans are required
to operate the equipment, but the faecal sludge is
not manually transported. Motorized transport can
be used with either motorized or manual emptying.
Nutrient Management
Treatment objective of treatment technologies
principally for management of Nitrogen, Phosphorous
and Potassium.
O-site sanitation
A sanitation system in which excreta (referred to
as wastewater) is collected and transported away
from the plot where they are generated. An o-site
sanitation system relies on a sewer technology for
transport.
On-site sanitation
A sanitation technology or system in which excreta
(referred to as faecal sludge) is collected and stored
and emptied from or treated on the plot where they
are generated.
Open drain
Open channel used to carry greywater, surface water
or stormwater.
Outlet
A pipe or hole through which wastewater is
discharged or a gas may vent.
Overow
An outlet for excess wastewater.
Pathogens
Disease-causing organisms (e.g. bacteria, helminths,
protozoa or viruses).
Plan
A detailed and time-limited proposal for achieving
stated objectives.
Policy
A course or principle of action adopted or proposed
by an organization or individual; A plan or course of
action, as of a government, political party, or business,
intended to influence and determine decisions,
actions, and other matters.
Public toilet
Not restricted to specic users; may be formally or
informally-managed.
Regulation
The action or process of regulating or being regulated.
Regulations
Rules or directives made and maintained by an
authority.
Risk
The likelihood and consequences that something
with a negative impact will occur.
Sanitary inspection
A sanitary inspection is an on-site inspection and
evaluation, by qualied individuals, of all conditions,
devices, and practices in the sanitation system that
pose an actual or potential danger to the health
and well-being of the various exposure groups. It
is a fact-nding activity that should identify system
deciencies - not only potential sources of hazardous
events, but also inadequacies and lack of integrity in
the system or that could lead to hazardous events.
Sanitation service chain
All components and processes comprising a sanitation
system, from toilet capture and containment through
emptying, transport, treatment (in-situ or o-site) and
nal disposal or end use.
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Sanitation system
A context specic series of sanitation technologies
(and services) for the management of faecal
sludge and/or wastewater through the stages of
containment, emptying, transport, treatment and
end use/disposal.
Sanitation technologies
The specific infrastructure, methods, or services
designed to support the process of managing faecal
sludge and/or wastewater through the stages of
containment, emptying, transport, treatment, and
end use/disposal.
Sanitation users
In this document refers to all people who use a toilet.
Sanitation workers
In this document refers to all people – employed or
otherwise – responsible for cleaning, maintaining,
operating or emptying a sanitation technology at any
step of the sanitation chain.
Separate (foul) sewer
A sewer that may carry blackwater and greywater but
from which stormwater is excluded.
Sewage
Wastewater that is transported through the sewer.
Sewer
An underground pipe that transports blackwater,
greywater and, in some cases, stormwater (combined
sewer) from individual households and other users
to treatment plants, using gravity or pumps when
necessary.
Sewerage
The physical sewer infrastructure for conveyance and
treatment of sewage.
Shared toilet
A single toilet shared between two or more
households.
Soak pit
A pit or chamber that allows euent to soak into the
surrounding ground.
Stabilization
A process achieved through the biodegradation of
the more readily degradable molecules, resulting
in faecal sludge with a lower oxygen demand. It is a
treatment objective of treatment technologies and
results in faecal sludge containing organic, carbon-
based molecules that are not readily degradable, and
which consists of more stable, complex molecules.
Standard
A required or agreed level of quality or attainment.
Stormwater
Stormwater is the general term for the rainfall runo
collected from roofs, roads and other surfaces before
owing towards low-lying land. It is the portion of
rainfall that does not inltrate into the soil.
Theory of Change
A comprehensive description and illustration of how
and why a desired change is expected to happen in
a particular context.
Toilet
The user interface with the sanitation system, where
excreta is captured; can incorporate any type of toilet
seat or latrine slab, pedestal, pan or urinal. There are
several types of toilet, for example pour- and cistern-
ush toilets, dry toilets and urine-diverting toilets.
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Treatment
Process/es that changes the physical, chemical and
biological characteristic or composition of faecal
sludge or wastewater so that it is converted into a
product that is safe for end use or disposal.
Urine
The liquid produced by the body to rid itself of urea
and other waste products. In this context, the urine
product refers to pure urine that is not mixed with
faeces or water.
User interface
User Interface describes the type of toilet, pedestal,
pan, or urinal with which the user comes in contact;
it is the way by which the user accesses the sanitation
system.
Wastewater
Used water from any combination of domestic
(households and services) industrial, stormwater
and any sewer inow/inltration.
Water body
Any substantial accumulation of water, both natural
and manmade (i.e. surface water).
WHO Guidelines
A WHO guideline is any document containing
recommendations about health interventions,
whether these are clinical, public health or policy
recommendations.
Notes
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GUIDELINES ON SANITATION
AND HEALTH
GUIDELINES ON SANITATION AND HEALTH
Safe sanitation is essential for health, from preventing infection to improving and maintaining mental and
social well-being.
Developed in accordance with the processes set out in the WHO Handbook for Guideline Development,
these guidelines provide comprehensive advice on maximizing the health impact of sanitation interventions.
They summarize the evidence on the links between sanitation and health, provide evidence-informed
recommendations, and offer guidance for international, national and local sanitation policies and
programme actions. The guidelines also articulate and support the role of health authorities in sanitation
policy and programming to help ensure that health risks are identied and managed eectively.
The audience for the guidelines is national and local authorities responsible for the safety of sanitation
systems and services, including policy makers, planners, implementers within and outside the health sector
and those responsible for the development, implementation and monitoring of sanitation standards and
regulations.
Department of Public Health, Environmental and Social Determinants of Health
World Health Organization
Avenue Appia 20
1211 Geneva 27
Switzerland
http://www.who.int/phe
ISBN 978 92 4 151470 5
WHO
